Final answer:
The expression 15 - 9 is factored using the GCF, which is 3, resulting in the factored expression 3(5 - 3).
Step-by-step explanation:
To factor the expression represented by 15 - 9 using the Greatest Common Factor (GCF), you first need to identify the GCF of the two numbers. Both 15 and 9 are divisible by 3, so 3 is the GCF. You will then divide both terms in the expression by 3 to factor it out. The factored expression would be 3(5 - 3). This shows that both terms originally had a factor of 3 which was factored out to simplify the expression.