=>(xy+yz)^3-3xy^2z(xy+yz)+(xz)^3-3x^2y^2z^2=0
=>(xy+yz+xz)^3[(xy+yz)^2-xz(xy+yz)+x^2z^2]-3xy^2z(xy+yz)-3x^2y^2z^2=0
=>(xy+yz+xz)^3*[(xy+yz)^2-xz(xy+yz)+x^2z^2]-3xy^2z(xy+yz+xz)=0
=>(xy+yz+xz)(x^2y^2+y^2z^2+x^2z^2-xy-yz-xz)=0
=>xy=yz=xz
=>x=y=z
=>M=(1+1)(1+1)(1+1)=8