-(1 / 3 + m square n + m cube) - (2 / 3-m square N-M cube) reduction

-(1 / 3 + m square n + m cube) - (2 / 3-m square N-M cube) reduction

-(1 / 3 + m square n + m cube) - (2 / 3-m square N-M cube)
=-m^3-m²n-1/3+m^3+m²n-2/3
=-1/3-2/3
=-1