Adding & Subtracting

Adding and Subtracting

Site: TBAISD Moodle
Course: Michigan Algebra I Preview 2012
Book: Adding & Subtracting
Printed by: Guest user
Date: Thursday, November 14, 2019, 01:51 AM

Table of contents

Adding

The four main operations of addition, subtraction, multiplication, and division can also be performed with functions. To add functions, combine like terms.

Example Given f(x) = 2x2 and g(x) = 3x2+ 1, what is f(x) + g(x)?

Step 1. Replace f(x) and g(x) with their equivalent expressions.

f(x) + g(x)

(2x2) + (3x2 + 1)

Step 2. Eliminate the parentheses and combine like terms.

2x2 + 3x2 + 1

5x2 + 1

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Subtracting

To subtract functions, first change the sign of every term being subtracted using the Distributive Property. Eliminate the parentheses and combine like terms.

Example Given f(x) = 2x2 and g(x) = 3x2+ 1, what is f(x) - g(x)?

Step 1. Replace f(x) and g(x) with their equivalent expressions.

f(x) - g(x)

(2x2) - (3x2 + 1)

Step 2. Use the Distributive Property to change the sign of every term of g(x).

2x2 - 3x2 - 1

Step 3. Combine like terms.

-1x2 - 1 or -x2 - 1

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Evaluating

Functions can also be added or subtracted given a domain value. First evaluate each function for the given domain then perform the indicated operation using the output values.

Example If f(x) = 2x2 and g(x) = 3x2 + 1, what is f(2) + g(3) ?

Step 1. Evaluate each function

f(2) = 2(2)2 = 8

g(3) = 3(3)2 + 1 = 28

Step 2. Add the output values of the two functions

f (2) + g(3)

= 8 + 28

= 36

Listen

Video Lesson

To learn how to add and subtract functions, please select the following link:

Add and Subtract Functions

Practice

Add and Subtract Functions Worksheet

Answer Key

Add and Subtract Functions Answer Key

Sources

Embracing Mathematics, Assessment & Technology in High Schools; A Michigan Mathematics & Science Partnership Grant Project

Holt, Rinehart & Winston, "Adding and Subtracting Functions." http://my.hrw.com/math06_07/nsmedia/lesson_videos/alg2/player.html?contentSrc=6480/6480.xml (accessed 8/10/2010).

Kuta Software, www.kutasoftware.com/free.html (accessed 07/19/2010).

Stapel, Elizabeth. "Function Notation: Introduction/Evaluation." http://www.purplemath.com/modules/fcnnot.htm (accessed 7/15/2010).