Question

If f(x)=2x^2 +4 and g(x)=x-3,which number satisfies f(x)=(f•g) (x)

Answer 1

$(f\cdot g)(x)=f(x)\cdot g(x)\\\\ (f\cdot g)(x)=(2x^2+4)(x-3)\\ (f\cdot g)(x)=2x^3-6x^2+4x-12\\\\ 2x^2+4=2x^3-6x^2+4x-12\\ 2x^3-8x^2+4x-16=0\\ 2x^2(x-4)+4(x-4)=0\\ (2x^2+4)(x-4)=0\\ 2(x^2+2)(x-4)=0\\ \boxed{x=4}$