algebra
posted by Casey .
Could someone show me how to solve system of equations by graphing?
9x9y=45
9y9x=45

Those two equations are really the same except for a sign change on both sides. They are not independent. Both will plot as the same line on a graph.
Since you have only one line instead of two intersecting lines, there is no single solution. Any x,y combination with yx=5 is a solution.