If the 5 points marked by dots are equally spaced, what is the value of y?

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1st point is 3
2nd is x
3rd is y
4th is blank
5th is 2x


Solution:
Let d=|x-3| 
then 
1) x=d+3
2) y=2d+3
3) 2x=4d+3 
and so we can say x=(1/2)(4d+3) 
from 1 and 3 
d+3=2d+1.5
d=1.5 
this means 
y=3+2(1.5)
y=6 

:)