Functional Notation

How would you write y = 2x - 3 in function notation?

• y = 2x-3

• f = 2x - 3

• f(x) = 2x-3

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 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, 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 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.

If f(x) = -3x - 8, find f(-1).

• f(-1) = 5

• f(-1) = -5

• f(-1) = -12

• f(-1) = -10

If f(x) = 6x - 9, find f(4).

• (4, 1)

• (4, 33)

• (4, 15)

• (4, -7)

Find f(10) if f(x)= 10x - 100.

• f(10) = 200

• f(10) = 0

• f(10) = -100

• f(10) = -99