Помогите ДАЮ 25 БАЛЛОВ
1. - ( - 2х + 7 ) - ( 2х - 1) =
2. 3а + ( 5b - 6а) + 7b =
3. - ( х - 3)+2 =
4. - 15 + ( -6 + у )=
5. - 15 - ( -6 + у ) =
6. ( а + 2b ) - ( 4а - b)=
7. ( 8а - b) - ( 3a - 5b) + ( 2a - 7b) =

1. 2х-7-2х+1=-62. 3а+5b-6a+7b=2b-3a3. 3-x+2=1-x4. -15-6+y=y+215. -15-(-6+y)=-9-y6. a+2b-4a+b=3b-3a=3(a-b)7. 8a-b-3a+5b+2a-7b=7a-3b