Answer:
\(2a\)
Step-by-step explanation:
We are asked to find GCF of \(18a\) and \(20ab\).
We can see that GCF of \(a\text{ and }ab\text{ is }a\).
Let us find greatest common factor of 18 and 20.
Factors of 20: 1, 2, 4, 5, 10, 20
Factors of 18: 1, 2, 3, 6, 9, 18.
We can see that GCF of 20 and 18 is 2.
Upon combining GCF of numerical part and variable part we will get: \(2a\)
Therefore, the greatest common factor of both expression is \(2a\).
