[tex]f(x) = 14x^2 - 10x, g(x) = 7x - 8[/tex]
We need to find (fog)(x). Question says composition functions
(fog)(9)= f (g (9))
First we find g(9)
[tex] g(x) = 7x - 8[/tex]
g(9)= 7(9) - 8 = 55
(fog)(9)= f (g (9))
Plug in 55 for g(9)
(fog)(9)= f (g (9)) = f(55)
Now we plug in 55 for x in f(x) and find f(55)
[tex]f(x) = 14(55)^2 - 10(55) = 41800[/tex]
so (fog)(9) = 41,800