题目内容
下列分解因式结果正确的是( )
A.a(a-1)-a+1=(a-1)(a+1) | ||||
B.-x2+xy-
| ||||
C.(x-y)3+(y-x)=(x-y)(x-y+1)(x-y-1) | ||||
D.-a(a+b)2-2(a+b)-1=-(a+b-1)2 |
A、a(a-1)-a+1=a(a-1)-(a-1)=(a-1)(a-1)=(a-1)2,故本选项错误;
B、-x2+xy-
y2=-(x-
y)2,故本选项错误;
C、(x-y)3+(y-x)=(x-y)[(x-y)2-1]=(x-y)(x-y+1)(x-y-1),故本选项正确;
D、-a(a+b)2-2(a+b)-1≠-(a+b-1)2,故本选项错误.
故选C.
B、-x2+xy-
1 |
4 |
1 |
2 |
C、(x-y)3+(y-x)=(x-y)[(x-y)2-1]=(x-y)(x-y+1)(x-y-1),故本选项正确;
D、-a(a+b)2-2(a+b)-1≠-(a+b-1)2,故本选项错误.
故选C.
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