Question

Сократить a^3+b^3/a+b + 3ab

Answer 1

$\frac{a^{3} +b^{3} }{a+b} +3ab=\frac{(a+b)(a^{2}-ab+b^{2}) }{a+b} +3ab=a^{2} -ab+b^{2}+3ab=a^{2} +2ab+b^{2} =(a+b)^{2}$