hello
[tex]\begin{gathered} f(x)=x^2+8 \\ g(x)=x+6 \end{gathered}[/tex][tex]\begin{gathered} (f\mathrm{}g)(-2)= \\ we\text{ find f.g first and the multiply the answer by -2} \end{gathered}[/tex][tex]\begin{gathered} f\mathrm{}g=(x^2+8)(x+6) \\ f\mathrm{}g=x^3+6x^2+8x+48 \end{gathered}[/tex]now we can find f.g(-2) by simply multiplying -2 all through f.g
[tex]\begin{gathered} (f\mathrm{}g)(-2)=(x^3+6x^2+8x+48)(-2) \\ (f\mathrm{}g)(-2)=-2x^3-12x^2-16x-96 \end{gathered}[/tex]