Ответ:
- \(ax+bx+ac+bc=x(a+b)+c(a+b)=(a+b)(x+c)\);
- \(3a-3c+xa-xc=3(a-c)+x(a-c)=(a-c)(x+3)\);
- \(4a+by+ay+4b=a(4+y)+b(y+4)=(a+b)(y+4)\);
- \(6x+7y+42+xy=6x+42+y(x+7)=6(x+7)+y(x+7)=(x+7)(y+6)\);
- \(px+py-5x-5y=p(x+y)-5(x+y)=(x+y)(p-5)\);
- \(ab-ac-4b+4c=a(b-c)-4(b-c)=(a-4)(b-c)\).
