Respuesta :
Answer: 16875x³-13500x²+3600x-320
Step-by-step explanation:
[gοfοh](x) means g(f(h(x))). So you plug in h(x) into f(x) and that into g(x).
f(3x)=5(3x)-4=15x-4
g(f(3x))=5(15x-4)³
g(f(3x))=5(3375x³-2700x²+720x-64)
g(f(3x))=16875x³-13500x²+3600x-320