作业帮-9(x+y)²+(x-y)² 因式分解
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-9(x+y)²+(x-y)² 因式分解
-9(x+y)²+(x-y)² 因式分解
-9(x+y)²+(x-y)² 因式分解
-9(x+y)²+(x-y)²
=(x-y)² -[3(x+y)]²
=[(x-y)-3(x+y)][(x-y)+3(x+y)]
=(x-y-3x-3y)(x-y+3x+3y)
=-（2x+4y）(4x+2y)
=-4(x+2y)(2x+y)
=[(x-y)-3(x+y)]*[(x-y)+3(x+y)]
来
-9(x+y)²+(x-y)²
=(x-y)²-9(x+y)²
=(x-y)²-【3(x+y)】²
=【(x-y)+3(x+y)】*【(x-y)-3(x+y)】
=（x-y+3x+3y)*(x-y-3x-3y)
=（4x+2y)*(-2x-4y)
=-2（2x+y)(x+2y)