Question

what is the greatest common factor of $12a$ and $9a^2$?
$12a^2$
36
$3a$
9

Explanation:

Step1: Factor coefficients

Prime factors of 12: $12 = 2^2 \times 3$
Prime factors of 9: $9 = 3^2$
GCF of coefficients: $3$

Step2: Factor variable terms

Term $12a$ has $a^1$, term $9a^2$ has $a^2$
GCF of variables: $a^1 = a$

Step3: Multiply GCF components

Multiply coefficient and variable GCFs: $3 \times a$

Answer:

3a