1
((y-8)(2y-1)-(3y+1)(5y-2)=2y²-y-16y+8-15y²+6y-5y+2=-13y²-16y+10
2
(x²+2y)(x³+7y)-6x³(x²-8y)=x^5+7x²y+2x³y+14y³-6x^5+48x³y=-5x^5+7x²y+50x³y
3
26x³-14x²y+8x²=2x²(13x-7y+4)
4
2m(a-b)+3n(b-a)=(a-b)(2m-3n)
5
(a-4)²-5(a-4)=(a-4)(a-4-5)=(a-4)(a-9)
6
a^6+a^4-3a²-3=a^4(a²+1)-3(a²+1)=(a²+1)(a^4-3)