Question

What is f(x) - g(x)?

Answer 1

$f(x)=9x^3+2x^2-5x+4\\\\g(x)=5x^3-7x+4\\\\f(x)-g(x)=(9x^3+2x^2-5x+4)-(5x^3-7x+4)\\\\=9x^3+2x^2-5x+4-5x^3+7x-4=9x^3-5x^3+2x^2-5x+7x+4-4\\\\=\boxed{4x^3+2x^2+2x}$