gcf is the grouping of all the factors common to both groups
lcm is a group of all the factors that has all the elements of both groups
factor
20x^2y^3=2*2*5*x*x*y*y*y
60x^3y^2=2*2*3*5*x*x*x*y*y
40xy^2=2*2*2*5*x*y*y
the GCF=2*2*5*x*y*y=20xy^2
the LCM=2*2*2*3*5*x*x*x*y*y*y=120x^3y^3