Question

Find the greatest common factor (GCF/HCF) of the following polynomial:
9x², 15x²y³, 6xy² and 21x²y²

Answer 1

The numerical coefficients of the given monomials are 9, 15, 6 and 21. The greatest common factor of 9, 15, 6 and 21 is 3.
The common literal appearing in the three monomials is x. 
The smallest power of x in the four monomials is 1.
The monomial of common literals with the smallest powers is x.
​Hence, the greatest common factor is 3x.