We could rewrite
2x + 3 = y
-4y + 8x = -12
as
2x - 1y = -3
8x - 4y = -12
We need to compare these two results. Do they represent the same equation or two different equations? Dividing the 2nd equation by 4 results in 2x - y = -3, which is indeed exactly the same as the first equation. Because of this, we have two straight lines that are superimposed; one lies right on top of the other. Thus, this system has an infinite number of solutions.
