1)ab+ac+xb+xc = a(b+c)+x(b+c) = (a+x)(b+c)
2)ab-ac+yb-yc = а(b-c)+y(b-c) = (a+y)(b-c)
3)4x-xy-4+x = 5x-xy-4 = x(5-y)-4
4)6ab-3a+2b-1 = 3a(2b-1)+2b-1 = (3a+1)(2b-1)
1)ab+ac+xb+xc = a(b+c)+x(b+c) = (a+x)(b+c)
2)ab-ac+yb-yc = а(b-c)+y(b-c) = (a+y)(b-c)
3)4x-xy-4+x = 5x-xy-4 = x(5-y)-4
4)6ab-3a+2b-1 = 3a(2b-1)+2b-1 = (3a+1)(2b-1)