Question

下列因式分解正确的是( )A.(x+2y)2=x2+4xy+4y2B.-x2+2...

下列因式分解正确的是( )A.(x+2y)2=x2+4xy+4y2B.-x2+2xy-y2=(x-y)2C.(x-y)2+4xy=(x+y)2D.(2x+y)2-(x+2y)2=(3x+3y)(x-y)

Answer 1

解答:解:A、是多项式乘法，故本选项错误;
B、应为-x2+2xy-y2=-(x-y)2，故本选项错误;
C、(x-y)2+4xy=(x+y)2，正确;
D、应为(2x+y)2-(x+2y)2=(3x+3y)(x-y)=3(x+y)(x-y)，故本选项错误.
故选C.