Question

m.n giúp e với ạ :<

1) xy + xz - 2y - 2z

2) x^2 - 6xy + 9y^2 - 25z^2

3) 3x^2 - 3y^2 - 12x + 12y

e cảm ơnnn

Answer 1

Lời giải:

1. $xy+xz-2y-2z=(xy+xz)-(2y+2z)$

$=x(y+z)-2(y+z)=(x-2)(y+z)$

2. $x^2-6xy+9y^2)-25z^2$

$=(x-3y)^2-(5z)^2=(x-3y-5z)(x-3y+5z)$
3.

$3x^2-3y^2-12x+12y=(3x^2-3y^2)-(12x-12y)=3(x^2-y^2)-12(x-y)=3(x-y)(x+y)-12(x-y)=3(x-y)(x+y-4)$