How to locate Two spots where electric potential is zero

[crazuiee]

Homework Statement

A positive charge of +q1 is located 3.00m to the left of a negative charge -q2. the charges have different magnitudes.
a) on the line through the center of the charges, the net electric field is zero at a spot 1.00m to the right of the negative charge. Determine the relative magnitude of the charges (charge ratio q1/q2)
b) on this line there are two spots where the potential is zero. locate these two spots relative to the negative charge.

Homework Equations

Ue=kq1q2/r
V=Ue/q
V=kq/r

The Attempt at a Solution

for part a i got q1=+16 and q2=-1
I'm not sure how to find these zero potential spots. I know they're supposed to be near the smaller negative value but I just can't figure out how to calculate out exactly where.

 

[Doc Al]

for part a i got q1=+16 and q2=-1

q1 and q2 are magnitudes and thus positive. You found that q1/q2 = 16. Good!

I'm not sure how to find these zero potential spots. I know they're supposed to be near the smaller negative value but I just can't figure out how to calculate out exactly where.

Write an expression for the total potential as a function of distance from the negative charge. You'll find it helpful to divide the line into 3 regions and write separate expressions for each region.