Hello all, I have two charges, q1 & q2, along a horizontal axis of length L. I supposed to determine the length at which another charge, Q, can be placed so that its net force is zero, other than infinitely away. I'm using the equation: F = kq1Q / r + kq2Q / r -- > kq1Q / (L+x)^2 = -( kq2Q / x^2 ) where x is the distance the point is away from L. I substitute my #s and I get the equation: (8 / (l^2 + 2xL + x^2)) = -(2/x^2) and then I get: 8x^2 = -2(L^2 + 2xL + x^2) -4x^2 = L^2 + 2xL + x^2 0 = L^2 + 2xL + 5x^2 Is this right? I cannot seem to solve for x. I thought I initially had it, but reworked through my math and realized I forgot to have 2q negative. What I initally got was: L^2 + 2xL - 3x^2 I can solve that by 'unfoiling' easily, but, as I previously mentioned, the math isn't correct to get that equation. Thank you for your help and have a wonderful day.