Question

if x+y+1=0, prove that x^3+y^3+1=3xy

Answer 1

I hope this will be write....

Answer 2

x+y=(-1)
x^3+y^3+1=(x+y)(x^2-xy+y^2)+1=(-1)*[(x+y)^2-3xy]+1
=  -1*(1-3xy)+1
=3xy