How do you evaluate f (x) = 3*3-4x+5

- - It'll be a lot easier if you clean up the function first.

You're not changing the function. You're just making it

easier to read and work on without mistakes.

Notice that 3x3=9, so the function is f (x) = 9 - 4x + 5

Combine like terms, and the function is f (x) = 14 - 4x.

Much easier to work with.

- - Now, when somebody tells you to evaluate the function for some number,

just take their number, write it in place of 'x', and see what you've got.

Example:

f (x) = 14 - 4x

Evaluate f (x) for x = 3.

- - Write 3 in place of 'x' in the function: f (3) = 14 - 4 (3)

- - 4 (3) = 12. So the function is f (3) = 14 - 12

- - Finish up the subtraction : f (3) = 2

You just evaluated f (x) for x=3.

Nice job!