С 2-12. Буду очень благодарен.​

Ответ:

2)7x-5x / 2y = 2x/2y=x/y

3)2x-8-4+10x/4x=12x-12 / 4x = 12(x-1)/4x=3(x-1)/x

4)3a+21/(a-7)(a+7)=3(a+7)/(a-7)(a+7)=3/a-7

5)8-a-3a+12/a-5=-4a+20/a-5=-4(a-5)/a-5=-4

6)x^2-2x-4x+9/(x-3)(x+3)=x^2-6x+9=(x-3)^2/(x-3)(x+3)=x-3/x+3

7)2/a-7/b=2b-7a/ab

8)3+5n/mn

9) 12-15/48pq=-3/48pq=-1/16pq

10)10x-5-5x-3/5(x-4)=5x-8/5(x-4)

11)5a+35-4a+12/20(2-a)=a+47/20(2-a)

12)c^2-8c+5c-c^2/(c-8)^2=-3c/(c-8)^2