Question

Daca $a^{2}- b^{2}$ =39 si a-b=3, calculati a+b

Answer 1

$a^{2} - b^{2} =(a-b)(a+b) =\ \textgreater \ (a-b)3=39 =\ \textgreater \ a+b= \frac{39}{3} =13$

Answer 2

a²-b²= (a-b)(a+b)            a-b = 3    a²-b² = 39
3(a+b) =39  ⇒  a+b = 13