Question

Find f(g(-4)) and g(f(-4)) using the functions below.

f(x) = 2x + 7
g(x) = x2 + 3x - 1

Answer 1

f(g(-4)) = 13.

g(f(-4)) = -3.

Explanation:

g(-4) = (-4)^2 + 3(-4) - 1

= 3.

so f(g(-4))

= f(3)

= 2(3) + 7

= 13.

f(-4) = 2(-4) + 7

= -1.

so g (f(-4))

= g(-1)

= (-1)^2 - 3 - 1

= -3.