Question

Given that f(x) = 2x + 5 and g(x) = x − 7, solve for f(g(x)) when x = −3.

Answer 1

f(x)=2x+5, g(x)=x-7

f(g(x))=2(x-7)+5=2x-14+5=2x-9

When x= -3:


`2\cdot (-3)-9=-6-9=\boxed{-15}`

:)

Answer 2

f(g(x)) is asking us to insert g(x) into each x of f(x).

f(g(x)) = 2(x - 7) + 5
f(g(x)) = 2x - 14 + 5
f(g(x)) = 2x - 9

If x = -3, then we need to find f(g(-3)).

f(g(-3)) = 2(-3) - 9
f(g(-3)) = -6 - 9
f(g(-3)) = -15