1) x(y-z)-y+z
2) 2b(x-y)+y-x
3) 5(c-b)+ab-ac
4) 2(x-c)-bx+bc

1) x(y-z)-y+z=x(y-z)-(y-z)=(x-1)(y-z)2) 2b(x-y)+y-x=2b(x-y)-(x-y)=(2b-1)(x-y)
3) 5(c-b)+ab-ac=5(c-b)-a(c-b)=(5-a)(c-b)
4) 2(x-c)-bx+bc=2(x-c)-b(x-c)=(2-b)(x-c)