Assuming that #(h*g)(x)=h(x)*g(x)#, we can either evaluate both functions separately and then multiply together, or we can combine the functions and then solve. Let's do the latter first, then the former:
#(h*g)(x)=(x^2-2x)(3x+5)#
#(h*g)(x)=3x^3+5x^2-6x^2-10x#
#(h*g)(x)=3x^3-x^2-10x#
Now, solve the function for #x=-4#
#(h*g)(-4)=3(-4)^3-(-4)^2-10(-4)#
#(h*g)(-4)=3(-64)-16+40#
#(h*g)(-4)=-192-16+40#
#color(green)((h*g)(-4)=-168#
Let's try solving each function separately, then combining:
#h(-4)=(-4)^2-2(-4)#
#h(-4)=16+8=color(blue)(24)#
#g(-4)=3(-4)+5#
#g(-4)=-12+5=color(red)(-7)#
#h(-4)*g(-4)=(h*g)(-4)=color(blue)(24)*color(red)((-7))#
#color(green)((h*g)(-4)=-168#
