Answer
$f(g(x))=-4x^3-4x^2+24$
$g(f(x))=-64x^3+16x^2-6$
Work Step by Step
f of g(x) means $f(g(x))$
$g(x)$ is given as $x^3+x^2-6$
Therefore $f(g(x))=-4(x^3+x^2-6)=-4x^3-4x^2+24$
g of f(x) means $g(f(x))$
$f(x)$ is given as $-4x$
Therefore $g(f(x))=(-4x)^3+(-4x)^2-6=-64x^3+16x^2-6$
