show graphically that the system of equations
3x-y=2
9x-3y=6
has infinitely many solutions
We have the following 2 equations of the lines
3x-y=2
9x-3y=6
So,
If x1/x2 = y1/y2 = c1/c2 than the lines are said to be co-incident and the lines have infinite solution.
In other words if you divide the second equation throughout by 3 you get the same equation as that of 1.
So the two lines are same when draw on a Cartesian plane.