Question

given f(x)= 3 square root x-5 , g(x)= x^3+1 find g f(x). Can someone explain to me this question step by step? I don’t know why I’m getting wrong answer pls help!

Answer 1

$f(x) = 3 \sqrt{x - 5} \\ g(x) = {x}^{3} + 1 \\ g(f(x)) = g(3 \sqrt{x - 5} )$

rewrite x in g(x)

$= {(3 \sqrt{x - 5}) }^{3} + 1 \\ = {3}^{3} \times {( \sqrt{x - 5} )}^{3} + 1 \\ = 27(x - 5) \sqrt{x - 5} + 1$

just observe ?