Răspunsuri

2014-04-17T00:43:11+03:00
a^2-b^2=(a-b)(a+b)=3(a+b)=39
⇒ a+b= \frac{39}{3}=13
2014-04-17T00:43:34+03:00
A²-b² este egal conform formulei cu (a-b)·(a+b)=39
Dar a-b=3 deci a+b=39÷3 = 13
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