Function Notation and Evaluating Functions

A company is selling bubble gum.  The function g(x)=3x+4 tells the company how much to charge if someone buys x packages of bubble gum.  Find g(8) and tell what it means within the context of the problem.

• g(8)=8.  This means that after 8 packages of gum, the company makes $8.

• g(8)=42.  This means that 8 packages of gum costs $42.

• g(8)=28.  This means that 8 packages of gum costs $28.

• g(8)=24.  This means that 8 packages of gum costs $24.

Ms. Brackemyer is collecting pencils.  The function p(x)=5x+12 tells us the total amount of pencils Ms. Brackemyer has after collecting for x number of days.  What is the meaning of p(8)=52?

• Ms. Brackemyer starts with 8 pencils and ends with 52.

• After 8 days, Ms. Brackemyer has 52 pencils.

• Ms. Brackemyer starts with 52 pencils and gets 4 more every day.

• Every day, Ms. Brackemyer gets 4 new pencils until she has 52.

How do you read f(x)?

• f x

• f of x

• f parenthesis x

• f with an x inside parenthesis

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 the function look like once you substitute in a 1 to find f(1)?

• f(x) = 21+1

• f(1) = 2 (1) + 1

• f(1) = 2x (1) + 1

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.

what is function notation?

• adding functions.

• i wasn't listening

• the way an equation (function) is written.

• pass.

Evaluate for f(1)

• 0

• -3

• 3

• 2

Evaluate for f(-5)

• 1

• 0

• 2

• -2

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

• 4

• 0

• 3

• 8