To find the value of f(g(-4)), we need to first substitute -4 into the definition of g(x) and then substitute the result into the definition of f(x).
First we substitute -4 into g(x):
g(-4) = 2(-4)^2 + 4(-4) - 8
g(-4) = 2(16) + (-16) - 8
g(-4) = 32 - 16 - 8
g(-4) = 8
Now we substitute 8 into f(x):
f(g(-4)) = f(8) = 2(8) - 4 = 16 - 4 = 12
So the value of f(g(-4)) is 12.