Question

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

Answer 1

`\large\boxed{(f\cdot g)(x)=2x^3+x^2-14x-7}`

Explanation:

`(f\cdot g)(x)=f(x)\cdot g(x)\\\\f(x)=2x+1;\ g(x)=x^2-7\\\\(f\cdot g)(x)=(2x+1)(x^2-7)\qquad\text{use FOIL:}\ (a+b)(c+d)=ac+ad+bc+bd\\\\=(2x)(x^2)+(2x)(-7)+(1)(x^2)+(1)(-7)\\\\=2x^3-14x+x^2-7`