To solve this, we have to simplify these numbers by adding like terms.
Next, we factor our expression. To do so, we look for the greatest common factor of 42 and 14, which is 14. We know that because 42 divided by 14 is 3.
f(g(-1)) = - 3
Evaluate g(-1) and substitute into f(x)
g(-1) = (-1)² -7(-1) - 9 = 1 + 7 - 9 = - 1
f(g(-1)) = (-1) - 2 = - 3