Question

prove that:

(x+y)^3 + (y+z)^3 + (z+x)^3 - 3(x+y)(y+z)(z+x) = 2(x^3 + y^3 + z^3 -3xyz)

Answer 1

Please look for the attachment.All you have to do is replace a,b and c with x,y and z.