Question

Надо разложить на множители.​

Answer 1

$\displaystyle\bf\\x^{3} +xy^{2} +13x^{2} y+13y^{3} =(x^{3} +xy^{2}) +(13x^{2} y+13y^{3}) =\\\\\\=x\cdot(x^{2} +y^{2} )+13y\cdot(x^{2} +y^{2} )=(x^{2} +y^{2} )\cdot(x+13y)$