Question

What is the common factor of 18 and 42

Answer 1

42- 14,7,6,3,2,24,1,42 <=== factors of 42

18- 9,2,3,6,1,18 <=== factors of 18

They share 6,3,2,1 <=== I would use 6, since it is the highest common factor

I hope this helps!
~kaikers

Answer 2

the common factor is 6

18 = 2 • 3 to the power of 2 (or else it will look like a 32)
42 = 2 • 3 • 7