We know that x³+y³+z³−3xyz=(x+y+z)(x²+y²+z²−xy−yz−zx)Given x+y+z=0x³+y³+z³−3xyz=(0)(x²+y²+z²−xy−yz−zx)⇒x³+y³+z³−3xyz=0⇒x³+y³+z³=3xyzHence proved.