Respuesta :

f(x) - g(x) = 9x^3 + 2x^2 - 5x + 4 - (5x^3 - 7x + 4)
f(x) - g(x) = 9x^3 + 2x^2 - 5x + 4 - 5x^3 + 7x - 4 
f(x) - g(x) = 4x^3 + 2x^2 + 2x ....combine like terms
f(x) - g(x) = 2x(2x^2 + x + 1) ...factor