Помогите решить. Даю 35 банкетов.

1
((y-8)(2y-1)-(3y+1)(5y-2)=2y-y-16y+8-15y+6y-5y+2=-13y-16y+10
2
(x+2y)(x+7y)-6x(x-8y)=x^5+7xy+2xy+14y-6x^5+48xy=-5x^5+7xy+50xy
3
26x-14xy+8x=2x(13x-7y+4)
4
2m(a-b)+3n(b-a)=(a-b)(2m-3n)
5
(a-4)-5(a-4)=(a-4)(a-4-5)=(a-4)(a-9)
6
a^6+a^4-3a-3=a^4(a+1)-3(a+1)=(a+1)(a^4-3)