Answer:
[tex]\large\boxed{(t\times s)(x)=4x^3-28x^2+3x-21}[/tex]
Step-by-step explanation:
[tex]s(x)=x-7\\t(x)=4x^2+3\\\\(t\times s)(x)=t(x)\times s(x)\\\\\text{Substitute:}\\\\(t\times s)(x)=(4x^2+3)(x-7)\\\\\text{use FOIL:}\ (a+b)(c+d)=ac+ad+bc+bd\\\\(t\times s)(x)=(4x^2)(x)+(4x^2)(-7)+(3)(x)+(3)(-7)\\\\=4x^3-28x^2+3x-21[/tex]