(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two charges of +4microC and +9microC are 30cm apart. Where on the line joining the charges is the electric field zero?

2. Relevant equations

Ep=E1+E2=0

E1=Kq1/x^2

E2=Kq2/(r-x)^2

3. The attempt at a solution

Since charges are alike, put Ep=E1-E2=0, then E1=E2

Substituted for E1 and E2

eventually leads to q1(r^2-2rx+x^2)=q2x^2

He told us to use quadratic since it's more secure, but that requires the (r^2-2rx+x^2) to be set equal to zero, which i cannot figure out how to do

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# Homework Help: Where along line is electric field zero?

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