When there are two variables ('x' and 'y'), then you need two equations
in order to find a solution.
If you only have one equation with 2 variables, then there are an infinite
number of solutions.
Here are a few solutions to this particular equation:
x = 0, y = -31
x = 1, y = -29
x = 2, y = -27
x = 3, y = -25
x = 15, y = -1
x = 20, y = 9
x = 30, y = 29
x = 40, y = 49
x = 50, y = 69
x = 100, y = 169
Now that you have these 10 solutions,
there are only an infinite number of others.
