Well, the linear equation can be expressed as y=ax+b in the solution of linear equations, there 3 main cases can be concluded as final lines. 1st case - the linear equation has no solution (for example, 0*x=5 has no solutions). 2nd case - the linear equation has one solution (for example 4*x=3 where the only one solution is x=0.75) and the 3rd case - the linear equation has infinite number of solutions (for example 0*x=0). So, in our case (3rd case) the last line can be concluded as 0=0.
