Question

F(x) = 4/x-9 g(x)=4/x + 9 find f(g(x))

Answer 1

Hello,

$f(x)= \dfrac{4}{x-9} \\ g(x)= \dfrac{4}{x+9} \\ f(g(x))=f( \dfrac{4}{x+9} )\\ = \dfrac{4}{ \dfrac{4}{x+9}-9} \\ = \dfrac{4(x+9)}{4-9x-81} \\ =- \dfrac{4x+36}{77x+9x}$