Question

what is the LCD??????????

Answer 1

$x^3+y^3=(x+y)(x^2-xy+y^2)\\\\ \text{lcd}\left(\dfrac{x}{x+y},\dfrac{x}{x^3+y^3}\right)=\text{lcm}(x+y,x^3+y^3)=(x+y)(x^2-xy+y^2)=\\ =x^3+y^3$