1) а³-ab-a²b+a²=(a³+a²)-(ab+a²b)=a²(a+1)-ab(1+a)=(a+1)(a²-ab)=a(a+1)(a-b)
2)x²y - x² - xy +x²= x²y-xy=xy(x-1)
3)ac² - c² - ac + c=c²(a-1)-c(a-1)=(a-1)(c²-c)=c(a-1)(c-1)
4) x²y - xy - x² +x=xy(x-1)-x(x-1)=(x-1)(xy-x)=(x-1)(x(y-1)
5) 2x + y +y²- 4x²=(2x+y)-(2x-y)(2x+y)=(2x+y)(1-2x+y)
6) a - 3b + 9b² - a²=(a-3b)-(a-3b)(a+3b)=(a-3b)(1-a-3b)
7) a² - 9b² +12bc - 4c²=a² -(3b-c)²=(a-(3b-c))(a+3b-c)=(a-3b+c)(a+3b-c)
8) 1-4x² - 4xy - y²=1-(4x²+4xy+y²)=1-(2x+y)²=(1-2x-y)(1+2x+y)