f(x)= 14x^3 + 15x^2 + 13x -10
g(x)= 15x^3 +13x^2 -10x +10
find g(-9) x f(8) - f(1) x f(-9)
And also-
f(x)=15x-11
g(x)=12x-14
find f(f(4))
