1. EXAMPLE 4
Finding the GCF of Monomials
Find the greatest common factor of 12a3 and 9a2.
STEP 1
Write the prime factorization of each expression.
12a3 = a a a
9a2 = a a

2. EXAMPLE 4
Finding the GCF of Monomials
Find the greatest common factor of 12a3 and 9a2.
STEP 2
Find the common factors, 3 and a2. The GCF is their product.
ANSWER
The GCF of 12a3 and 9a2 is 3 a2, or 3a2.

3. GUIDED PRACTICE
for Example 4
Find the greatest common factor of the monomials.
x, 18x

4. GUIDED PRACTICE
for Example 4
ANSWER
The GCF of 6x and 18x is x, or 6x.

5. GUIDED PRACTICE
for Example 4
Find the greatest common factor of the monomials.
xy, 4xy2

6. GUIDED PRACTICE
for Example 4
ANSWER
The GCF of 6xy and 4xy2 is or 2xy
2 x y

7. GUIDED PRACTICE
for Example 4
Find the greatest common factor of the monomials.
y, 9x2y2

8. GUIDED PRACTICE
for Example 4
ANSWER
3 y
The GCF of 15y and 9x2y2 is

9. GUIDED PRACTICE
for Example 4
Find the greatest common factor of the monomials.
xy3, 10x2y2

10. GUIDED PRACTICE
for Example 4
ANSWER
The GCF of 5xy3 and 10x2y2 is or 5xy2
5 x y2