Electric potential PRoblem , dont understand

[th3plan]

Homework Statement

In the picture i attached, particles with charges q1 = +7e and q2 = -15e are fixed in place with a separation of d = 23.9 cm. With V = 0 at infinity, what are the finite (a) positive and (b) negative values of x (in cm) at which the net electric potential on the x-axis is zero?



I don't understand why for positive net electric potential is in the middle between them, and negative is to the left. Can someone explain this.

 

[Doc Al]

For each of the three regions (x < 0, 0 < x < d, x > d), write an expression that describes the net potential as a function of position.

What's the electric potential surrounding a point charge?

 

[th3plan]

How would i do that, my book doesn't require us to write functions. I don't know what the electric potential surround a point charge is

 

[Doc Al]

How would i do that, my book doesn't require us to write functions.

By "function" I just mean a mathematical formula.

I don't know what the electric potential surround a point charge is

There's no point in worrying about the potential from two charges until you understand how to find the potential from one charge. Look it up!