g(x)= x^2-4x f(x)=2x-6 g(f(x))

g(x) = x² - 4x      f(x) = 2x - 6

g(f(x)) = (2x - 6)² - 4 * (2x - 6) = 4x² - 24x + 36 - 8x + 24 = 4x² - 32x + 60

Ответ : g(f(x)) = 4x² - 32x + 60