To find the volume of a triangle we need to do base x height we can see that the base is 13m and the height is 6m so the answer would be
13m x 6m = 78m
I hope this picture helps you a little bit!
If you don't understand, I'll try to explain more :)
To find G of F first solve f(x) by replacing x with -7
F(x) = x^2 +6
= -7^2 +6
= 49 +6 = 55
So f(x) = 55
Now replace the X in the g(x) equation with 55
g(x) = x+8 / x
= 55+8 / 55
= 63/55
The last choice is the correct answer.