Question

Given f (x) = 4x - 7; g(x) = x +3, what is the value of (g o f) (4)?

Answer 1

`(g circ f)(4)=color(magenta)(12)`

Explanation:

Within this explanation, I will use the notation `g(f(x))` instead of the given form `(g circ f)`; I find it easier to understand.

If `g(color(blue)x)=color(blue)x+3`
and `color(red)(f(x))=color(red)(4x-7)`
then
`color(white)("XXX")g(color(red)(f(x)))=color(red)(4x-7)+3`

`color(white)("XXXXXXX")=4x-4`

and if `g(f(color(green)x))=4color(green)x-4`
then
`color(white)("XXX")g(f(color(green)4))=4 * color(green)4 -4`

`color(white)("XXXXXXX")=16-4`

`color(white)("XXXXXXX")=12`