first) find f(7), which is simply plugging in 7 where the x is in f(x)

and you will get f(7)=9

then take what you find for f(7) and plug it into g(x)

so.. g(x) becomes g(9), plug 9 in for all x and evaluate

g(f(7)) = 160

Secondly) for this one, take the equation g(x) and put it into f(x) where the x is

so you will get

f(x) = 3 sqrt((2x^2-2)+2)

=3*sqrt(2)*x

First find f(7) = 3*sqrt(9) = 9

Then g(f(7) = g(9) = 2*9^2 - 2 = 160 OK!