Consider the functions f(x) = x2 − 13 and g(x) = x + 5. what is the value of f[g(−4)]?

First find g(-4) 
so :
g(-4) = (-4) + 5 
g(-4) = 1 

then find f(g(-4)) which means to substitute the value of g(-4) in for x in f(x) 
so:
f(1) = 1^2 - 13
f(1) = 1 -13 
f(1) = -12