Приводим все к общему знаменателю
1. (8(x-4)(x-1)-80-3(x^2-1))/(x^2-1)=0
(8x^2-40x+32-80-3x^2+3)/(x^2-1)=0
(5x^2-40x-45)/(x^2-1)=0
(5(x+1)(x-9))/(x-1)(x+1)=0
5(x-9)/(x-1)=0
x=9, x=1
2. ((x+1)(x+3)-9(x-3)-24)/(x-3)(x+3)=0
(x^2+4x+3-9x+27-24)/(x-3)(x-3)=0
(x^2-5x+6)/(x-3)(x+3)=0
(x-2)(x-3)/(x-3)(x+3)=0
(x-2)/(x+3)=0
x=2, x=-3
3. ((x+1)^2-4-(x-1)^2)/(x-1)(x+1)=0
(x^2+2x+1-4-x^2+2x-1)/(x-1)(x+1)=0
4(x-1)/(x-1)(x+1)=0
4/(x+1)=0
x=-1
4. ((x-3)(x-1)-(x-9)(x+5)-48)/(x+5)(x-1)=0
(x*2-4x+3-x^2+4x+45-48)/(x+5)(x-1)=0
0/(x+5)(x-1)=0
x-любое число