\(x_1=6cm\) and \(x_2=21cm\)¡A¤¤¶¡ÂI¦ì¸m\(x=\frac{6+21}{2}=13.5cm\)

\(q_1=-q_2=-2.00*10^{-7}C\)

\(\vec{E}_1=-\frac{|q_1|}{4\pi\epsilon_0(x-x_1)^2}\hat{i}\)

\(\vec{E}_2=-\frac{|q_2|}{4\pi\epsilon_0(x-x_2)^2}\hat{i}\)

\(\vec{E}_{net}=\vec{E}_1+\vec{E}_2=-6.39*10^5N/C\)