Function Notation

If a question asks you to find f(2), what does that mean?

• Let x = 2

• Let y = 2

If f(x) = 2x + 1, what would be your first step to find f(1)?

• Plug a 1 in for all the x's

• Set the function equal to 1

• Only plug a 1 into the left side

• Only plug a 1 into the right side

If f(x) = 2x + 1, find f(1).

• f(1) = 1

• f(1) = 4

• f(1) = 0

• f(1) = 3

If I know that f(2) = 4, what is another way I can write my answer?

• 2,4

• (2, 4)

• That is the only way to write it.

Evaluate f(-2) if f(x) = x + 3

• -1
• 1
• 5
• -5

Given f(x) =
2x² + 5x - 17, find f(-1). 

• f(-1) = -20
• f(-1) = -24

What is f(1)?

• 1
• 5
• 0
• 4

What is x if
f(x) = -2?

• 4
• 0
• 3
• 8

What is f(8)? 

• 8
• 0
• 3
• -2

Given g(x) =
 4x - 7, find g(-9). 

• g(-9) = 29
• g(-9) = -43