The expression has three monomials: 2xyz, 3x2y and 4y2. The numerical coefficients of the given monomials are 2, 3 and 4. The greatest common factor of 2, 3 and 4 is 1.The common literal appearing in the three monomials is y. The smallest power of y in the three monomials is 1.The monomial of common literals with the smallest powers is y.​Hence, the greatest common factor is y.