Answer :

If two lines are parallel, then they must have the same slope.
So, let's take the equation y=1/2x-6(equal to y=x/2-6) and just change the y intercept
1. y=1/2x
2.y=1/2x+3
3.y=1/2x-7
4.y=1/2x+4
5.y=1/2x-8
and so on...