Question

LCM of 9, 12, and 18

Answer 1

36

I hope that's right.

Answer 2

Break this up into factors.
9=3x3
12=3x2x2
18=3x3x2

Looking at these factor sets, you need at least 2 3's (for the 9 and 18) and at least 2 2's (for the 12).  Since we want the LOWEST multiple, then multiply the factors needed.  2x2x3x3=36.

Hope this helps!