There are three monomials such that the greatest common factor of the first and second monomials is 2xy, and the greatest common factor of the second and third monomials is 2x2y. The greatest common factor of the three monomials is
let:
m1 = 2xy a
m2 = 2xy b
m3 = 2x2y c
since 2 and 3 have a common factor let b=2n
m1 = 2xy a
m2 = 2xy 2 n
m3 = 2x2y c
or simply
m1 = 2xy a
m2 = 2xy 2n
m3 = 2xy 2c
given that anc have no common factors
