1. а) х²-ху-4х+4у
б) аb - ac- bx+cx+c-6
2. -2ab³ × 3a² × bв4степени.

x²-xy-4x+4y=(x²-xy)-(4x-4y)=x(x-y)-4(x-y)=(x-y)(x-4)ab-ac-bx+cx+c-b=(ab-ac)-(bx-cx)+(c-b)=a(b-c)-x(b-c)-(b-c)=(b-c)(a-x-1)-2ab³ * 3a² * b⁴=-6a³b⁷