2a-2b/a+b÷a²-b²/a²+2ab+b² 等于多少

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2a-2b/a+b÷a²-b²/a²+2ab+b² 等于多少

2a-2b/a+b÷a²-b²/a²+2ab+b² 等于多少
2a-2b/a+b÷a²-b²/a²+2ab+b² 等于多少

2a-2b/a+b÷a²-b²/a²+2ab+b² 等于多少
(2a-2b)/(a+b)÷(a²-b²)/(a²+2ab+b² )
=(2a-2b)/(a+b)*(a²+2ab+b²)/(a²-b²)
=2(a-b)/(a+b)*(a+b)²/(a-b)(a+b)
=2

(2a-2b)/(a+b)÷(a²-b²)/(a²+2ab+b²)
=[2(a-b)/(a+b)][(a²+2ab+b²) /(a²-b²)]
=[2(a-b)/(a+b)](a+b)² /[(a-b)(a+b)]
=[2(a-b)/(a+b)](a+b) /(a-b)]
=2