1) b(12a+b)(3)
2)5yx(x+2y)(4)
3)x^3(5-7x)(1)
4)(x-y)(1-7b)(2)
5)5y(x+1)+b(x+1)=(x+1)(5y+b)(2)
6)3x^2y(x+2y-xy)(4)
7)-x^2(x-1)+x(x-1)(x-1)=(x-1)(-x^2+x(x-1))=(x-1)(-x^2+x^2-x)=-x(x-1)=x(1-x)(3)
8)3(x-y)-y(x-y)=(x-y)(3-y)(1)
9)5(a-b)-x(a-b)+(a-b)=(a-b)(5-x+1)=(a-b)(6-x)(2)
10)a^2(a+3)+2a(a+3)+(a+3)=(a+3)(a^2+2a+1)=(a+3)(a+1)^2(4)
11)(2a-b)(4a^2+2ab+b^2)-(4a^2+2ab+b^2)=(4a^2+2ab+b^2)(2a-b-1)(1)