Question

Lets see....who can solve it​

Answer 1

$\frac{x}{y} + \frac{y}{x} = - 1 \\ \frac{ {x}^{2} + {y}^{2} }{xy} = - 1 \\ {x}^{2} + {y}^{2} = - xy \\ {x}^{2} + xy + {y}^{2} = 0$
again
${x}^{3} - {y}^{3} \\ (x - y)( {x}^{2} + xy + {y}^{2} ) \\ (x - y)(0) \\ 0$
hence the value of x³- y³ = 0