Physics
posted by Chloe .
A charge q =+ 4.11 x 10  9 C is placed at the origin, and a second charge equal to 2q is placed on the x axis at the location x = +1.00 m. (a) Find the electric potential midway between the two charges. (b) The electric potential vanishes at some point between the charges. Find this value of x.

Well, it turns out potential is scalar, so you just add. Find where they add to zero.

I don't understand what you're trying to say when you're saying to add. Can you elaborate more?

Vtotal=V1+V2=kq1/x +kq2/x, you know distancex (1/2 of 1), and you know the two q.
when is potential zero> Set Vtotalt to zero, and solve. one distance x, the other 1x.
You can do that. 
Ok that makes much more sense. Thank you for your help!