Verify that : x3+y3+z3−3xyz=12(x+y+z)[(x−y)2+(y−z)2+(z−x)2)]
We need to verify that x3+y3+z3−3xyz=12(x+y+z)[(x−y)2+(y−z)2+(z−x)2)]
R.H.S= 12(x+y+z)[(x−y)2+(y−z)2+(z−x)2)]
= 12(x+y+z)[x2+y2−2xy+y2+z2−2yz+z2+x2−2xz]
=12(x+y+z)[2x2+2y2+2z2−2xy−2yz−2xz]
=12(x+y+z)2(x2+y2+z2−xy−yz−xz)
=(x+y+z)2(x2+y2+z2−xy−yz−xz)=L.H.S because it is an identity.