Đáp án:
Giải thích các bước giải:
1) `ax-ay+bx-by=a(x-y)+b(x-y)=(a+b)(x-y)`
2) `x^2-4x+xy-4y=x(x-4)+y(x-4)=(x+y)(x-4)`
3) `2ab+3c+6b+ac=2b(a+3)+c(a+3)=(2b+c)(a+3)`
4) `xz+yz-5(x+y)=z(x+y)-5(x+y)=(z-5)(x+y)`
5) `x^2-xy+x-y=x(x-y)+(x-y)=(x+1)(x-y)`
6) `x^3+3x^2+3x+9=x^2(x+3)+3(x+3)=(x^2+3)(x+3)`
7) `x+x^2-x^3-x^4=x(1+x)-x^3(1+x)=(x^3+x)(1+x)=x(x^2+1)(1+x)`
8) `x^2-xy-2x+2y=x(x-y)-2(x-y)=(x-2)(x-y)`