The problem statement, all variables and given/known data http://img210.imageshack.us/img210/3239/q1ae6.jpg [Broken] The attempt at a solution Kq1q3/(L+x)2 = Kq2q3/(x)2 q1/(L+x)2 = q2/(x)2 I came up with the question above. But when I plug in the numbers I get 2 different answers. For x, I got -7.363450837 and -21.73332335. I tired both answers in the system and I got it wrong. I am not sure why this is happening. Do I have to add +11 to the x to get the real answer? If so then to which one do I add 11 to?