You can put this solution on YOUR website! It's a straight line, so you need just 2 points.
7x=x+2y
6x = 2y
y = 3x
Find 2 points.
Give x a value and find y.
@x = 0, y = 0 --> (0,0)
@x = 3, y = 9 --> (3,9)
Plot the 2 points, draw a line thru them.
---------------
For graphs, get the free software from www.padowan.dk.com/graph/