问题 解答题

因式分

(1)(a+b)2+6(a+b)+9;

(2)-2xy-x2-y2

(3)(x2-2xy)2+2y2(x2-2xy)+y4

答案

(1)(a+b)2+6(a+b)+9,

=(a+b+3)2

(2)-2xy-x2-y2

=-(x2+2xy+y2),

=-(x+y)2

(3)(x2-2xy)2+2y2(x2-2xy)+y4

=(x2-2xy+y22

=(x-y)4

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