Answer: (x^2/3-25)/(x-125)
Explanation:
(f(x)-f(125))/(x-125)=
((x^2/3+5)-(125^2/3+5))/(x-125)=
(x^2/3+5-25-5)/(x-125)=
(x^2/3-25)/(x-125) <==Most simplified answer
(x^1/3-5)/(x^2/3-5x^1/3-25) <== Substitute x^2/3 with x^2 and things will be more clear