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题型:解答题 题类:常考题 难易度:普通
(1)x2﹣2xy+y2
(2)x2﹣y2 .
3+2 =2+2 +1=( )2+2 +1=( +1)2;
5+2 =2+2 +3=( )2+2× × +( )2=( + )2
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