All you have to do is rotate the current dots, and bam.
5/6 = .83333333333333333333333333.... It goes on...
.833333333333333333 * 18 = 15
15 is your answer
Another way you could do it is 18/6 = 3
3+3+3+3+3 = 15
3 being 1/6th of 18 *Hope This Helps...*
Answer:
1
Step-by-step explanation:

3x+12=5x-21
-5x -5x
-2x + 12 = -21
-12 -12
-2x=-33
x = 16.5