Помогите хотяб
.......

(5x/(x-10) +20x/(x²-20x +100) :(4x-24)/(x² -100) -25x/(x-10) =
((5x(x-10) +20x) / (x-10)²)*(x-10)(x+10)/4(x-6) - 25x/(x-10) =
(5x(x-6) / (x-10)²)*(x-10)(x+10)/4(x-6) - 25x/(x-10) =
(5x / (x-10))*(x+10)/4 - 25x/(x-10) =5x(x+10) / 4(x-10) - 25x/(x-10) =
=(5x(x+10) -4*25x) / 4(x-10)=5x(x+10 -20)/4(x-10)=5x(x-10)/4(x-10) = 5x/4.   || для x≠6 ; x≠10 ||

---------
(4x-24)/(a² -100)  ? заменено на  (4x-24)/(x² -100)