数学因式分解。啊。拜托了。第一题X^2－Y^2－5X－5Y。 第二题x^2-y^2-2yz-z^2 第三题y^2(x-y)+z^2(y-z...

1.原式等于=(x+y)(x-y)-5(x+y)=(x+y)(x-y-5)
2.原式等于=x^2-(y+z)^2=(x+y+z)(x-y-z)
3原式等于=xy^2+yz^2-(y+z)(y^2-yz+z^2)=(z+y)^2y-y^3-(y+z)(y^2+z^2-yz)=-z^3+2y^2z=z(2y^2-z^2)=z(根号2y+z)(根号2y-z)
4.原式等于=（2x-5)(2x-1)
5.原式等于=（x-a)(x+b)
6.原式等于=x^2+4x+4+xy+2y=(x+2)^2+y(x+2)=(x+2)(x+2+y)
7.原式等于=x(2ax-3)+2ax-3=(2ax-3)(x+1)

X^2－Y^2－5X－5Y=(x-y)(x+y)-5(x+y)=(x+y)(x-y-5);
x^2-y^2-2yz-z^2=x^2-(y^2+2yz+z^2)=(x+y+z)(x-y-z)
y^2(z-y)+z^2(y-z)=(z-y)(y^2-z^2)=(z-y)(y-z)(y+z)=-(y-z)^2(y+z)
4x^2-12x+5=(2x-5)(2x-1)
x^2-(a-b)x-ab=(x-a)(x+b)
x^2+4+xy+2y+4x=(x^2+4x+4)+(x+2)y=(x+2)^2+(x+2)y=(x+2)(x+2+y)
2ax^2-3x+2ax-3=(2ax-3)x+(2ax-3)=(2ax-3)(x+1)
注意：第3题题目有问题

x^2是x的平方吗?

去v