Đa thức trên tương đương với đa thức:
\(\left(xy\left(x+y\right)+xyz\right)+\left(yz\left(y+z\right)+xyz\right)+\left(xz\left(x+z\right)+xyz\right)\)
=\(xy\left(x+y+z\right)+yz\left(x+y+z\right)+xz\left(x+y+z\right)\)
=\(\left(x+y+z\right)\left(xy+yz+xz\right)\)
xy(x + y) + yz( y + z )+ zx( z + x ) + 3xyz
=xy(x + y) + xyz + yz(y + z) + xyz + xz(x + z)+xyz
=zy(x + y + z) + yz(x + y + z) + xz(x + y + z)
=(x + y + z)(xy + yz + zx)
chúc bn hok tốt