Question

HELP PLEASE, I don't understand this at all!

Answer 1

Given $f(x)=8x-9$, they want you to find $f(4).$

This is basically evaluating a function. Simply put 4 into x of the function.

Hence,

$f(4)=8(4)-9=23$

ANSWER: 23

Answer 2

f(x) = 8x-9

f(4)

let x=4 and substitute in

f(4) = 8*4 -9

f(4) = 32-9

f(4) = 23