Răspunsuri

2014-10-02T00:27:01+03:00
(a-b)²=(a-b)·(a-b)=a²-a·b-a·b+b²=a²-2·a·b+b²
(a-b)³=(a-b)·(a-b)·(a-b)=(a²-2·a·b+b²)·(a-b)=a³-a²·b-2a³b+2ab²+ab²-b³=a³-3a²b+3ab²-b³


(a+b)³=(a+b)·(a+b)·(a+b)=(a²+2·a·b+b²)·(a+b)=a³-a²·b+2a³b+2ab²+ab²+b³=a³+3a²b+3ab²+b³
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