Question

If s(x)=x-7 and t(x) =4x^2+3 which expression is equivalent to (t×s)(x)​

Answer 1

`\large\boxed{(t* s)(x)=4x^3-28x^2+3x-21}`

Explanation:

`s(x)=x-7\\t(x)=4x^2+3\\\\(t* s)(x)=t(x)* s(x)\\\\\text{Substitute:}\\\\(t* s)(x)=(4x^2+3)(x-7)\\\\\text{use FOIL:}\ (a+b)(c+d)=ac+ad+bc+bd\\\\(t* s)(x)=(4x^2)(x)+(4x^2)(-7)+(3)(x)+(3)(-7)\\\\=4x^3-28x^2+3x-21`