Add and Subtract Polynomials

Determine the Degree of Polynomials

We have learned that a term is a constant or the product of a constant and one or more variables. A monomial is an algebraic expression with one term. When it is of the form $a x^{m},$ where a is a constant and m is a whole number, it is called a monomial in one variable. Some examples of monomials in one variable are $2 x, 5 y, 17 z,$ and $4 y^{2}$ . Monomials can also have more than one variable such as $5 a b c$ and $−4 a^{2} b^{3} c^{2} .$

A monomial, or two or more monomials combined by addition or subtraction, is a polynomial. Some polynomials have special names, based on the number of terms. A monomial is a polynomial with exactly one term. A binomial has exactly two terms, and a trinomial has exactly three terms. There are no special names for polynomials with more than three terms.

Here are some examples of polynomials.

Polynomial	$y + 1$	$4 a^{2} - 7 a b + 2 b^{2}$	$4 x^{4} + x^{3} + 8 x^{2} - 9 x + 1$
Monomial	14	$8 y^{2}$	$−9 x^{3} y^{5}$	$−13 a^{3} b^{2} c$
Binomial	$a + 7 b$	$4 x^{2} - y^{2}$	$y^{2} - 16$	$3 p^{3} q - 9 p^{2} q$
Trinomial	$x^{2} - 7 x + 12$	$9 m^{2} + 2 m n - 8 n^{2}$	$6 k^{4} - k^{3} + 8 k$	$z^{4} + 3 z^{2} - 1$

Notice that every monomial, binomial, and trinomial is also a polynomial. They are just special members of the “family” of polynomials and so they have special names. We use the words monomial, binomial, and trinomial when referring to these special polynomials and just call all the rest polynomials.

The degree of a polynomial and the degree of its terms are determined by the exponents of the variable.

A monomial that has no variable, just a constant, is a special case. The degree of a constant is 0.

Let’s see how this works by looking at several polynomials. We’ll take it step by step, starting with monomials, and then progressing to polynomials with more terms.

Let's start by looking at a monomial. The monomial $8 a b^{2}$ has two variables a and b. To find the degree we need to find the sum of the exponents. The variable a doesn't have an exponent written, but remember that means the exponent is 1. The exponent of b is 2. The sum of the exponents, $1 + 2,$ is 3 so the degree is 3.

The polynomial is 8 a b squared. The exponents of the variables are 1 and 2 so the degree of the monomial is 1 plus 2 which equals 3.

Here are some additional examples.

Monomial examples: 14 has degree 0, 8 a b squared has degree 3, negative 9 x cubed y to the fifth power has degree 8, negative 13 a has degree 1. Binomial examples: The terms in h plus 7 have degree 1 and 0 so the degree of the whole polynomial is 1. The terms in 7 b squared minus 3 b have degree 2 and 1 so the degree of the whole polynomial is 2. The terms in z squared y squared minus 25 have degree 4 and 0 so the degree of the whole polynomial is 4. The terms in 4 n cubed minus 8 n squared have degree 3 and 2 so the degree of the whole polynomial is 3. Trinomial examples: The terms in x squared minus 12 x plus 27 have degree 2, 1 and 0 so the degree of the whole polynomial is 2. The terms in 9 a squared plus 6 a b plus b squared have degree 2, 2, and 2 so the degree of the whole polynomial is 2. The terms in 6 m to the fourth power minus m cubed n squared plus 8 m n to the fifth power have degree 4, 5, and 6 so the degree of the whole polynomial is 6. The terms in z to the fourth power plus 3 z squared minus 1 have degree 4, 2, and 0 so the degree of the whole polynomial is 4. Polynomial examples: The terms in y minus 1 have degree 1 and 0 so the degree of the whole polynomial is 1. The terms in 3 y squared minus 2 y minus 5 have degree 2, 1, 0 so the degree of the whole polynomial is 2. The terms in 4 x to the fourth power plus x cubed plus eight x squared minus 9 x plus 1 have degree 4, 3, 2, 1, and 0 so the degree of the whole polynomial is 4.

Working with polynomials is easier when you list the terms in descending order of degrees. When a polynomial is written this way, it is said to be in standard form of a polynomial. Get in the habit of writing the term with the highest degree first.

Determine whether each polynomial is a monomial, binomial, trinomial, or other polynomial. Then, find the degree of each polynomial.

ⓐ $7 y^{2} - 5 y + 3$ ⓑ $−2 a^{4} b^{2}$ ⓒ $3 x^{5} - 4 x^{3} - 6 x^{2} + x - 8$ ⓓ $2 y - 8 x y^{3}$ ⓔ 15

Solution

	Polynomial	Number of terms	Type	Degree of terms	Degree of polynomial
ⓐ	$7 y^{2} - 5 y + 3$	3	Trinomial	2, 1, 0	2
ⓑ	$−2 a^{4} b^{2}$	1	Monomial	6	6
ⓒ	$3 x^{5} - 4 x^{3} - 6 x^{2} + x - 8$	5	Polynomial	5, 3, 2, 1, 0	5
ⓓ	$2 y - 8 x y^{3}$	2	Binomial	1, 4	4
ⓔ	15	1	Monomial	0	0

Add and Subtract Polynomials

We have learned how to simplify expressions by combining like terms. Remember, like terms must have the same variables with the same exponent. Since monomials are terms, adding and subtracting monomials is the same as combining like terms. If the monomials are like terms, we just combine them by adding or subtracting the coefficients.

Add or subtract: ⓐ $25 y^{2} + 15 y^{2}$ ⓑ $16 p q^{3} - (−7 p q^{3}) .$

Solution

ⓐ
$\begin{matrix} 25 y^{2} + 15 y^{2} \\ Combine like terms. & 40 y^{2} \end{matrix}$

ⓑ
$\begin{matrix} 16 p q^{3} - (−7 p q^{3}) \\ Combine like terms. & 23 p q^{3} \end{matrix}$

Remember that like terms must have the same variables with the same exponents.

Simplify: ⓐ $a^{2} + 7 b^{2} - 6 a^{2}$ ⓑ $u^{2} v + 5 u^{2} - 3 v^{2} .$

Solution

ⓐ

Example demonstrating the simplification of an algebraic expression by combining like terms.
	$a^{2} + 7 b^{2} - 6 a^{2}$
Combine like terms.	$−5 a^{2} + 7 b^{2}$

ⓑ

Illustrates a polynomial with no like terms to combine, demonstrating an expression that remains unchanged after an attempt at simplification.
	$u^{2} v + 5 u^{2} - 3 v^{2}$
There are no like terms to combine. In this case, the polynomial is unchanged.	$u^{2} v + 5 u^{2} - 3 v^{2}$

We can think of adding and subtracting polynomials as just adding and subtracting a series of monomials. Look for the like terms—those with the same variables and the same exponent. The Commutative Property allows us to rearrange the terms to put like terms together.

Find the sum: $(7 y^{2} - 2 y + 9) + (4 y^{2} - 8 y - 7) .$

Solution

Steps to simplify an algebraic expression by identifying and combining like terms.
Identify like terms.	$(\underset{____}{\underset{____}{7 y^{2}}} - \underset{___}{2 y} + 9) + (\underset{____}{\underset{____}{4 y^{2}}} - \underset{___}{8 y} - 7)$
Rewrite without the parentheses, rearranging to get the like terms together.	$\underset{_________}{\underset{_________}{7 y^{2} + 4 y^{2}}} - \underset{_______}{2 y - 8 y} + 9 - 7$
Combine like terms.	$11 y^{2} - 10 y + 2$

Be careful with the signs as you distribute while subtracting the polynomials in the next example.

Find the difference: $(9 w^{2} - 7 w + 5) - (2 w^{2} - 4) .$

Solution

Step-by-step subtraction of polynomials, illustrating the process of simplifying an algebraic expression.
	$(9 w^{2} - 7 w + 5) - (2 w^{2} - 4)$
Distribute and identify like terms.	$\underset{____}{\underset{____}{9 w^{2}}} - \underset{___}{7 w} + 5 - \underset{____}{\underset{____}{2 w^{2}}} + 4$
Rearrange the terms.	$\underset{__________}{\underset{__________}{9 w^{2} - 2 w^{2}}} - \underset{___}{7 w} + 5 + 4$
Combine like terms.	$7 w^{2} - 7 w + 9$

To subtract $a$ from $b,$ we write it as $b - a,$ placing the $b$ first.

Subtract $(p^{2} + 10 p q - 2 q^{2})$ from $(p^{2} + q^{2}) .$

Solution

Step-by-step simplification of an algebraic expression by distributing, rearranging, and combining like terms.
	$(p^{2} + q^{2}) - (p^{2} + 10 p q - 2 q^{2})$
Distribute.	$p^{2} + q^{2} - p^{2} - 10 p q + 2 q^{2}$
Rearrange the terms, to put like terms together.	$p^{2} - p^{2} - 10 p q + q^{2} + 2 q^{2}$
Combine like terms.	$−10 p q + 3 q^{2}$

Find the sum: $(u^{2} - 6 u v + 5 v^{2}) + (3 u^{2} + 2 u v) .$

Solution

Steps to simplify an algebraic expression by combining like terms.
	$(u^{2} - 6 u v + 5 v^{2}) + (3 u^{2} + 2 u v)$
Distribute.	$u^{2} - 6 u v + 5 v^{2} + 3 u^{2} + 2 u v$
Rearrange the terms to put like terms together.	$u^{2} + 3 u^{2} - 6 u v + 2 u v + 5 v^{2}$
Combine like terms.	$4 u^{2} - 4 u v + 5 v^{2}$

When we add and subtract more than two polynomials, the process is the same.

Simplify: $(a^{3} - a^{2} b) - (a b^{2} + b^{3}) + (a^{2} b + a b^{2}) .$

Solution

Step-by-step simplification of a polynomial expression.
	$(a^{3} - a^{2} b) - (a b^{2} + b^{3}) + (a^{2} b + a b^{2})$
Distribute.	$a^{3} - a^{2} b - a b^{2} - b^{3} + a^{2} b + a b^{2}$
Rewrite without the parentheses, rearranging to get the like terms together.	$a^{3} - a^{2} b + a^{2} b - a b^{2} + a b^{2} - b^{3}$
Combine like terms.	$a^{3} - b^{3}$

Evaluate a Polynomial Function for a Given Value

A polynomial function is a function defined by a polynomial. For example, $f (x) = x^{2} + 5 x + 6$ and $g (x) = 3 x - 4$ are polynomial functions, because $x^{2} + 5 x + 6$ and $3 x - 4$ are polynomials.

In Graphs and Functions, where we first introduced functions, we learned that evaluating a function means to find the value of $f (x)$ for a given value of x. To evaluate a polynomial function, we will substitute the given value for the variable and then simplify using the order of operations.

For the function $f (x) = 5 x^{2} - 8 x + 4$ find: ⓐ $f (4)$ ⓑ $f (−2)$ ⓒ $f (0) .$

Solution

ⓐ



Simplify the exponents.
Multiply.
Simplify.

ⓑ



Simplify the exponents.
Multiply.
Simplify.

ⓒ



Simplify the exponents.
Multiply.
Simplify.

The polynomial functions similar to the one in the next example are used in many fields to determine the height of an object at some time after it is projected into the air. The polynomial in the next function is used specifically for dropping something from 250 ft.

The polynomial function $h (t) = −16 t^{2} + 250$ gives the height of a ball t seconds after it is dropped from a 250-foot tall building. Find the height after $t = 2$ seconds.

Solution

This table illustrates the step-by-step calculation of the height of an object at t=2 seconds using the function h(t) = -16t^2 + 250, resulting in a height of 186 feet.
	$h (t) = −16 t^{2} + 250$
To find $h (2),$ substitute $t = 2 .$	$h (2) = −16 {(2)}^{2} + 250$
Simplify.	$h (2) = −16 \cdot 4 + 250$
Simplify.	$h (2) = −64 + 250$
Simplify.	$h (2) = 186$
	After 2 seconds the height of the ball is 186 feet.

Add and Subtract Polynomial Functions

Just as polynomials can be added and subtracted, polynomial functions can also be added and subtracted.

For functions $f (x) = 3 x^{2} - 5 x + 7$ and $g (x) = x^{2} - 4 x - 3,$ find:

ⓐ $(f + g) (x)$ ⓑ $(f + g) (3)$ ⓒ $(f - g) (x)$ ⓓ $(f - g) (−2) .$

Solution

ⓐ



Rewrite without the parentheses.
Put like terms together.
Combine like terms.

ⓑ In part (a) we found

(f + g) (x)

and now are asked to find

(f + g) (3) .

Step-by-step evaluation of the function (f+g)(x) = 4x^2 - 9x + 4 at x=3.
	$(f + g) (x) = 4 x^{2} - 9 x + 4$
To find $(f + g) (3),$ substitute $x = 3 .$	$(f + g) (3) = 4 {(3)}^{2} - 9 \cdot 3 + 4$
	$(f + g) (3) = 4 \cdot 9 - 9 \cdot 3 + 4$
	$(f + g) (3) = 36 - 27 + 4$

Notice that we could have found $(f + g) (3)$ by first finding the values of $f (3)$ and $g (3)$ separately and then adding the results.

Find $f (3) .$


Find $g (3) .$


Find $(f + g) (3) .$

ⓒ



Rewrite without the parentheses.
Put like terms together.
Combine like terms.

ⓓ

The image demonstrates the process of evaluating the function (f-g)(x) = 2x^2 - x + 10 at x = -2, showing step-by-step substitution and calculation to arrive at the result (f-g)(-2) = 20.

Key Concepts

Monomial
- A monomial is an algebraic expression with one term.
- A monomial in one variable is a term of the form $a x^{m},$ where a is a constant and m is a whole number.
Polynomials
- Polynomial—A monomial, or two or more algebraic terms combined by addition or subtraction is a polynomial.
- monomial —A polynomial with exactly one term is called a monomial.
- binomial — A polynomial with exactly two terms is called a binomial.
- trinomial —A polynomial with exactly three terms is called a trinomial.
Degree of a Polynomial
- The degree of a term is the sum of the exponents of its variables.
- The degree of a constant is 0.
- The degree of a polynomial is the highest degree of all its terms.

Practice Makes Perfect

Determine the Type of Polynomials

In the following exercises, determine if the polynomial is a monomial, binomial, trinomial, or other polynomial. Then, indicate the degree of the polynomial.

ⓐ $47 x^{5} - 17 x^{2} y^{3} + y^{2}$
ⓑ $5 c^{3} + 11 c^{2} - c - 8$
ⓒ $\frac{5}{9} a b + \frac{1}{3} b$
ⓓ 4
ⓔ $4 p q + 17$

Solution

ⓐ trinomial, 5 ⓑ polynomial, 3 ⓒ binomial, 2 ⓓ monomial, 0
ⓔ binomial, 2

ⓐ $x^{2} - y^{2}$
ⓑ $−13 c^{4}$
ⓒ $a^{2} + 2 a b - 7 b^{2}$
ⓓ $4 x^{2} y^{2} - 3 x y + 8$
ⓔ 19

ⓐ $8 y - 5 x$
ⓑ $y^{2} - 5 y z - 6 z^{2}$
ⓒ $y^{3} - 8 y^{2} + 2 y - 16$
ⓓ $81 a b^{4} - 24 a^{2} b^{2} + 3 b$
ⓔ $−18$

Solution

ⓐ binomial, 1ⓑ trinomial, 2
ⓒ polynomial, 3ⓓ trinomial, 5
ⓔ monomial, 0

ⓐ $11 y^{2}$
ⓑ $−73$
ⓒ $6 x^{2} - 3 x y + 4 x - 2 y + y^{2}$
ⓓ $4 y^{2} + 17 z^{2}$
ⓔ $5 c^{3} + 11 c^{2} - c - 8$

ⓐ $5 a^{2} + 12 a b - 7 b^{2}$
ⓑ $18 x y^{2} z$
ⓒ $5 x + 2$
ⓓ $y^{3} - 8 y^{2} + 2 y - 16$
ⓔ $−24$

Solution

ⓐ $trinomial, 2$ ⓑ $monomial, 4$ ⓒ $binomial, 1$ ⓓ $polynomial, 3$
ⓔ $monomial, 0$

ⓐ $9 y^{3} - 10 y^{2} + 2 y - 6$
ⓑ $−12 p^{3} q$
ⓒ $a^{2} + 9 a b + 18 b^{2}$
ⓓ $20 x^{2} y^{2} - 10 a^{2} b^{2} + 30$
ⓔ 17

ⓐ $14 s - 29 t$
ⓑ $z^{2} - 5 z - 6$
ⓒ $y^{3} - 8 y^{2} z + 2 y z^{2} - 16 z^{3}$
ⓓ $23 a b^{2} - 14$
ⓔ $−3$

Solution

ⓐ $binomial, 1$ ⓑ $trinomial, 2$ ⓒ $polynomial, 3$ ⓓ $binomial, 3$
ⓔ $monomial, 0$

ⓐ $15 x y^{}$
ⓑ 15
ⓒ $6 x^{2} - 3 x y + 4 x - 2 y + y^{2}$
ⓓ $10 p - 9 q$
ⓔ $m^{4} + 4 m^{3} + 6 m^{2} + 4 m + 1$

Add and Subtract Polynomials

In the following exercises, add or subtract the monomials.

ⓐ ${7x}^{2} + 5 x^{2}$
ⓑ $4a - 9 a$

Solution

ⓐ ${12x}^{2}$ ⓑ $− 5a$

ⓐ ${4y}^{3} + 6 y^{3}$
ⓑ $− y - 5 y$

ⓐ $−12 w + 18 w$
ⓑ $7 x^{2} y - (−12 x^{2} y)$

Solution

ⓐ $6 w$ ⓑ $19 x^{2} y$

ⓐ $−3 m + 9 m$
ⓑ $15 y z^{2} - (−8 y z^{2})$

${7x}^{2} + 5 x^{2} + 4a - 9 a$

Solution

${12x}^{2} - 5a$

${4y}^{3} + 6 y^{3} - y - 5 y$

$−12 w + 18 w + 7 x^{2} y - (−12 x^{2} y)$

Solution

$6 w + 19 x^{2} y$

$−3 m + 9 m + 15 y z^{2} - (−8 y z^{2})$

ⓐ $−5 b - 17 b$
ⓑ $3 x y - (−8 x y) + 5 x y$

Solution

ⓐ $−22 b$ ⓑ $16 x y$

ⓐ $−10 x - 35 x$
ⓑ $17 m n^{2} - (−9 m n^{2}) + 3 m n^{2}$

ⓐ $12 a + 5 b - 22 a$
ⓑ $p q^{2} - 4 p - 3 q^{2}$

Solution

ⓐ $−10 a + 5 b$
ⓑ $p q^{2} - 4 p - 3 q^{2}$

ⓐ $14x - 3 y - 13 x$
ⓑ $a^{2} b - 4 a - 5 a b^{2}$

ⓐ $2 a^{2} + b^{2} - 6 a^{2}$
ⓑ $x^{2} y - 3 x + 7 x y^{2}$

Solution

ⓐ $−4 a^{2} + b^{2}$
ⓑ $x^{2} y - 3 x + 7 x y^{2}$

ⓐ $5 u^{2} + 4 v^{2} - 6 u^{2}$
ⓑ $12a + 8 b$

ⓐ $x y^{2} - 5 x - 5 y^{2}$
ⓑ $19y + 5 z$

Solution

ⓐ $x y^{2} - 5 x - 5 y^{2}$
ⓑ $19 y + 5 z$

$12 a + 5 b - 22 a + p q^{2} - 4 p - 3 q^{2}$

$14x - 3 y - 13 x + a^{2} b - 4 a - 5 a b^{2}$

Solution

$x - 3 y + a^{2} b - 4 a - 5 a b^{2}$

$2 a^{2} + b^{2} - 6 a^{2} + x^{2} y - 3 x + 7 x y^{2}$

$5 u^{2} + 4 v^{2} - 6 u^{2} + 12a + 8 b$

Solution

$− u^{2} + 4 v^{2} + 12a + 8 b$

$x y^{2} - 5 x - 5 y^{2} + 19y + 5 z$

Add: $4 a, −3 b, −8 a$

Solution

$− 4a - 3 b$

Add: $4x, 3 y, −3 x$

Subtract $5 x^{6}$ from $−12 x^{6}$

Solution

$−17 x^{6}$

Subtract $2 p^{4}$ from $−7 p^{4}$

In the following exercises, add the polynomials.

$(5 y^{2} + 12 y + 4) + (6 y^{2} - 8 y + 7)$

Solution

$11 y^{2} + 4 y + 11$

$(4 y^{2} + 10 y + 3) + (8 y^{2} - 6 y + 5)$

$(x^{2} + 6 x + 8) + (−4 x^{2} + 11 x - 9)$

Solution

$−3 x^{2} + 17 x - 1$

$(y^{2} + 9 y + 4) + (−2 y^{2} - 5 y - 1)$

$(8 x^{2} - 5 x + 2) + (3 x^{2} + 3)$

Solution

$11 x^{2} - 5 x + 5$

$(7 x^{2} - 9 x + 2) + (6 x^{2} - 4)$

$(5 a^{2} + 8) + (a^{2} - 4 a - 9)$

Solution

$6 a^{2} - 4 a - 1$

$(p^{2} - 6 p - 18) + (2 p^{2} + 11)$

In the following exercises, subtract the polynomials.

$(4 m^{2} - 6 m - 3) - (2 m^{2} + m - 7)$

Solution

$2 m^{2} - 7 m + 4$

$(3 b^{2} - 4 b + 1) - (5 b^{2} - b - 2)$

$(a^{2} + 8 a + 5) - (a^{2} - 3 a + 2)$

Solution

$11 a + 3$

$(b^{2} - 7 b + 5) - (b^{2} - 2 b + 9)$

$(12 s^{2} - 15 s) - (s - 9)$

Solution

$12 s^{2} - 16 s + 9$

$(10 r^{2} - 20 r) - (r - 8)$

In the following exercises, subtract the polynomials.

Subtract $(9 x^{2} + 2)$ from $(12 x^{2} - x + 6)$

Solution

$3 x^{2} - x + 4$

Subtract $(5 y^{2} - y + 12)$ from $(10 y^{2} - 8 y - 20)$

Subtract $(7 w^{2} - 4 w + 2)$ from $(8 w^{2} - w + 6)$

Solution

$w^{2} + 3 w + 4$

Subtract $(5 x^{2} - x + 12)$ from $(9 x^{2} - 6 x - 20)$

In the following exercises, find the difference of the polynomials.

Find the difference of $(w^{2} + w - 42)$ and $(w^{2} - 10 w + 24)$

Solution

$11 w - 66$

Find the difference of $(z^{2} - 3 z - 18)$ and $(z^{2} + 5 z - 20)$

In the following exercises, add the polynomials.

$(7 x^{2} - 2 x y + 6 y^{2}) + (3 x^{2} - 5 x y)$

Solution

$10 x^{2} - 7 x y + 6 y^{2}$

$(−5 x^{2} - 4 x y - 3 y^{2}) + (2 x^{2} - 7 x y)$

$(7 m^{2} + m n - 8 n^{2}) + (3 m^{2} + 2 m n)$

Solution

$10 m^{2} + 3 m n - 8 n^{2}$

$(2 r^{2} - 3 r s - 2 s^{2}) + (5 r^{2} - 3 r s)$

In the following exercises, add or subtract the polynomials.

$(a^{2} - b^{2}) - (a^{2} + 3 a b - 4 b^{2})$

Solution

$−3 a b + 3 b^{2}$

$(m^{2} + 2 n^{2}) - (m^{2} - 8 m n - n^{2})$

$(p^{3} - 3 p^{2} q) + (2 p q^{2} + 4 q^{3}) - (3 p^{2} q + p q^{2})$

Solution

$p^{3} - 6 p^{2} q + p q^{2} + 4 q^{3}$

$(a^{3} - 2 a^{2} b) + (a b^{2} + b^{3}) - (3 a^{2} b + 4 a b^{2})$

$(x^{3} - x^{2} y) - (4 x y^{2} - y^{3}) + (3 x^{2} y - x y^{2})$

Solution

$x^{3} + 2 x^{2} y - 5 x y^{2} + y^{3}$

$(x^{3} - 2 x^{2} y) - (x y^{2} - 3 y^{3}) - (x^{2} y - 4 x y^{2})$

Evaluate a Polynomial Function for a Given Value

In the following exercises, find the function values for each polynomial function.

Solution

ⓐ 187 ⓑ 40 ⓒ 2

Solution

In the following exercises, find the height for each polynomial function.

A painter drops a brush from a platform 75 feet high. The polynomial function $h (t) = −16 t^{2} + 75$ gives the height of the brush t seconds after it was dropped. Find the height after $t = 2$ seconds.

Solution

The height is 11 feet.

A girl drops a ball off a 200-foot cliff into the ocean. The polynomial $h (t) = −16 t^{2} + 200$ gives the height of the ball, in feet, t seconds after it is dropped. Find the height after $t = 3$ seconds.

A manufacturer of stereo sound speakers has found that the revenue received from selling the speakers at a cost of p dollars each is given by the polynomial function $R (p) = −4 p^{2} + 420 p .$ Find the revenue received when $p = 60$ dollars.

Solution

The revenue is $10,800.

A manufacturer of the latest basketball shoes has found that the revenue received from selling the shoes at a cost of p dollars each is given by the polynomial $R (p) = −4 p^{2} + 420 p .$ Find the revenue received when $p = 90$ dollars.

The polynomial $C (x) = 6 x^{2} + 90 x$ gives the cost, in dollars, of producing a rectangular container whose top and bottom are squares with side x feet and height 6 feet. Find the cost of producing a box with $x = 4$ feet.

Solution

The cost is $456.

The polynomial $C (x) = 6 x^{2} + 90 x$ gives the cost, in dollars, of producing a rectangular container whose top and bottom are squares with side x feet and height 4 feet. Find the cost of producing a box with $x = 6$ feet.

Add and Subtract Polynomial Functions

$f (x) = 2 x^{2} - 4 x + 1$ and $g (x) = 5 x^{2} + 8 x + 3$

Solution

$f (x) = 4 x^{2} - 7 x + 3$ and $g (x) = 4 x^{2} + 2 x - 1$

$f (x) = 3 x^{3} - x^{2} - 2 x + 3$ and $g (x) = 3 x^{3} - 7 x$

Solution

ⓐ $(f + g) (x) = 6 x^{3} - x^{2} - 9 x + 3$
ⓑ $(f + g) (2) = 29$
ⓒ $(f - g) (x) = − x^{2} + 5 x + 3$
ⓓ $(f - g) (−3) = −21$

$f (x) = 5 x^{3} - x^{2} + 3 x + 4$ and $g (x) = 8 x^{3} - 1$

Writing Exercises

Using your own words, explain the difference between a monomial, a binomial, and a trinomial.

Solution

Answers will vary.

Using your own words, explain the difference between a polynomial with five terms and a polynomial with a degree of 5.

Ariana thinks the sum $6 y^{2} + 5 y^{4}$ is $11 y^{6} .$ What is wrong with her reasoning?

Solution

Answers will vary.

Is every trinomial a second degree polynomial? If not, give an example.

Self Check

ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

The figure shows a table with six rows and four columns. The first row is a header row and it labels each column. The first column header is “I can…”, the second is "confidently", the third is “with some help”, “no minus I don’t get it!”. Under the first column are the phrases “identify polynomials, monomials, binomials, and trinomials”, “determine the degree of polynomials”, “add and subtract monomials”, “add and subtract polynomials”, and “evaluate a polynomial for a given value”. Under the second, third, fourth columns are blank spaces where the learner can check what level of mastery they have achieved.

ⓑ If most of your checks were:

…confidently. Congratulations! You have achieved the objectives in this section. Reflect on the study skills you used so that you can continue to use them. What did you do to become confident of your ability to do these things? Be specific.

…with some help. This must be addressed quickly because topics you do not master become potholes in your road to success. In math every topic builds upon previous work. It is important to make sure you have a strong foundation before you move on. Whom can you ask for help?Your fellow classmates and instructor are good resources. Is there a place on campus where math tutors are available? Can your study skills be improved?

…no - I don’t get it! This is a warning sign and you must not ignore it. You should get help right away or you will quickly be overwhelmed. See your instructor as soon as you can to discuss your situation. Together you can come up with a plan to get you the help you need.

binomial

A binomial is a polynomial with exactly two terms.

degree of a constant

The degree of any constant is 0.

degree of a polynomial

The degree of a polynomial is the highest degree of all its terms.

degree of a term

The degree of a term is the sum of the exponents of its variables.

monomial

A monomial is an algebraic expression with one term. A monomial in one variable is a term of the form

a x^{m},

where a is a constant and m is a whole number.

polynomial

A monomial or two or more monomials combined by addition or subtraction is a polynomial.

standard form of a polynomial

A polynomial is in standard form when the terms of a polynomial are written in descending order of degrees.

trinomial

A trinomial is a polynomial with exactly three terms.

polynomial function

A polynomial function is a function whose range values are defined by a polynomial.