Answer:
INFINITE number of solutions
Explanation:
In order to solve by graphing, we proceed to convert the second equation into slope-intercept form to make it easier to find a couple of coordinate pairs. As we do such, we find that the two equations given are EXACTLY the SAME equation:

Then when we plot both equations, we get the exact same line (both lines overlap). We use for example the points (0, 4) and (2, -1)
This gives us the graph shown in the attached image, from which we conclude that we have an INFINITE number of solutions (all the points that reside on the lines).