the difference of x/25x-125-1/x^2-5x
(x/25x-125)-1/(x^2-5x)= x / 25(x-5) - 1/ x(x-5) = (1/x-5)(x/25-1/x) factorized by 1/x-5, and (1/x-5)(x/25-1/x) = (1/x-5)(x²-25/25x)= (1/x-5) [(x-5)(x+5) / 25x]
= (x+5) / 25x simplified by x-5
so the final answer is
x/25x-125-1/x^2-5x = (x+5) / 25x