Electric Potential-finding unknown distance

[abspeers]

Homework Statement

A 1.5 10-9 C charge is at the origin, and a -1.50 10-9 C charge is 4.5 m to the right on the positive x-axis. The electric potential is -1.8 V at a point on the x-axis that is a distance d to the right of the negative charge. Find d.

Homework Equations

V = k [sum] (q/r)

The Attempt at a Solution

-1.8V = k [(1.5 x 10-9 / 4.5 + x ) + (-1.5 x 10-9 / x )]

Maybe I'm doing the algebra incorrectly, but I continue to get the wrong answer although I think the set-up is correct.

 

[ehild]

The Attempt at a Solution

-1.8V = k [(1.5 x 10-9 / 4.5 + x ) + (-1.5 x 10-9 / x )]

Maybe I'm doing the algebra incorrectly, but I continue to get the wrong answer although I think the set-up is correct.

The equation is incorrect, it should be

-1.8V = k [1.5 x 10-9 / (4.5 + x ) + (-1.5 x 10-9 / x )]

Show how do you get x.

ehild