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## Homework Statement

Charge Q1 and charge -3Q are 1 meter apart. Consider only points on the axis between the charges. A.) Where is V=0? B.) Where is E=0?

## Homework Equations

[tex]V=\frac{kQ}{r}[/tex]

## The Attempt at a Solution

A.) The positions where the electric potential would be zero would be to add the potentials due to the individual charges and set equal to Zero, correct?

[tex]V=\frac{kQ_1}{r_1}-\frac{k3Q}{r_2}=0[/tex]

[tex]r_1+r_2=1[/tex]

[tex]r_1=1-r_2[/tex]

[tex]V=\frac{kQ_1}{1-r_2}-\frac{k3Q}{r_2}=0[/tex]

After this, the algebra gets very messy and I can't figure out how to approach it to isolate r_2.

B.) Haven't attempted this yet. Hints on how to from part A to B?