Answer:
3
Step-by-step explanation:
<h3><em>Step 1) list out all the factors</em></h3>
18: 1, 2, 3, 6, 9, 18
39: 1, 3, 13, 39
<h3><em>Step 2) find the greatest factor both numbers have (Greatest Common Factor)</em></h3>
18: 1, 2,<u> 3</u>, 6, 9, 18
39: 1, <u>3</u>, 13, 39
<h3><em>Step 4) that number is your GCF</em></h3>
3
