Question

分解因式（过程）

（y-x)^2 -(x+y)(x-y)
-a^2 -b^2 +2ab+4

Answer 1

（y-x)^2 -(x+y)(x-y)
=(x-y)²-(x+y)(x-y)
=(x-y)(x-y-x-y)
=-2y(x-y)
-a^2 -b^2 +2ab+4
=-(a²-2ab+b²)+4
=4-(a-b)²
=(2+a-b)(2-a+b)
=(a-b+2)(b-a+2)

Answer 2

（y-x)^2-(x+y)(x-y)
=y^2-2xy+x^2-x^2+y^2
=2y^2-2xy
=2y(y-x)
-a^2-b^2+2ab+4
=-[(a^2+b^2-2ab)-4]
=-[(a-b)^2-4]
=-(a-b+2)(a-b-2)

Answer 3

（y-x)^2 -(x+y)(x-y)
=(x-y)^2-(x+y)(x-y)
=(x-y)(x-y-x-y)
=-2y(x-y)

-a^2 -b^2 +2ab+4
=-(a-b)^2+4
=(2+a-b)(2-a+b)

Answer 4

你后面的那个2是平方吗？