Question 920579
                        -14x+7y=21
                         -8x+4y=12

    If you multiply the top equation by -8 and the bottom equation by 14 so that the x's cancel each other out, you get... 

                      -112x -56y = 168
                       112x +56y = -168

Surprise,surprise because when you add the equations together, they cancel each other totally out.  This is a case when the graph of line 1 is the same as line 2.  They are the same line.  They are not parallel, but are the same line.  There will be infinite amount of solutions.