body{margin:0;} noscript{z-index: 10000; position: fixed; display: block; height: 100%; width: 100%; background: #fff;} noscript .fa{font-size: 40px; display:block; color: #daa520;} noscript div{margin-top: 6%; padding-left: 20px; padding-right: 20px; text-align: center;} ! You must have JavaScript enabled to use this site.

Big Ideas Math Integrated I, 2016

BI

Big Ideas Math Integrated I, 2016 View details

3. Function Notation

Finish the assignment

Continue to next subchapter

Exercise 4 Page 123

Substitute 21 for f(x).

x=2

Practice makes perfect

To find the value of x that will make the function equal to 21, we will substitute 21 for f(x) in the given function rule. Then, we can solve for x.

f(x)=6x+9

f(x)= 21

21=6x+9

LHS-9=RHS-9

12=6x

.LHS /6.=.RHS /6.

2=x

Rearrange equation

x=2

When x=2, the function equals 21.

Checking Our Answer

Verifying Our Solution

We can verify our solution by substituting x=2 into the function and evaluating.

f(x)=6x+9

x= 2

f( 2)=6( 2)+9

Multiply

f(2)=12+9

Add terms

f(2)=21

When x=2, f(x)=21, so our solution is correct.

Subchapter links

Communicate Your Answer p.121

Monitoring Progress p.122-124

Exercises p.125-126