Question

x в 3 степени +у в 3 степени+2xy(x+y)

Answer 1

$x^3+y^3+2xy(x+y)=(x^3+y^3)+2xy(x+y)= \\ =(x+y)(x^2-xy+y^2)+2xy(x+y)= \\ =(x+y)(x^2-xy+y^2+2xy)=(x+y)(x^2+xy+y^2)$