Question

Given f(x)=4x+6 and g(x)=9x+9
then what is f(g(−6))?

Answer 1

f(x)=4x+6
g(x)=9x+9f(g(−6))

f(x)·g(x) = (4x+6)(9x+9)
f(x)·g(x) = 36x^2 +36x+54x+54
f(x)·g(x) = 36x^2 +90x+54
f(x)·g(x) = 36(-6)^2 +90(-6)+54
f(x)·g(x) = 36(36)+90(-6)+54
f(x)·g(x) = 1296+(-540)+54
f(x)·g(x) = 1296-540+54
f(x)·g(x) = 810
f(g(−6)) = 810

Answer 2

To solve this question, you can break it into 2 parts. First evaluate the function g(X)=9x+9 for g(-6). Which is g(-6) = 9(-6)+9 = -45. Then evaluate f(-45). F(-45)= 4(-45)+6= -180+6= -174. The final answer for f(g(-6))= -174.