Упростите выражение:
1. (2а+с)(а-2с)+а(2с-а)=
2. (2x+y)(x+y)-6y(x-y)=
3. (5x-b)(3x+b)+(3x-b)(b+x)=
4. (+3)(c-2)-(c+1)(c-2)=
5. (y-4)(y-3)+(y+8)(y-1)=
6. (a-6)(a+4)-(a-8)(a-3)=
7. 5b(b+8)+(b-7)(b-8)=
8. 5b(p-7)-(p-6)(p+5)=