Theo culong: \(F=k\dfrac{\left|q_1q_2\right|}{\varepsilon r^2}\Rightarrow\left|q_1q_2\right|=\dfrac{\varepsilon Fr^2}{k}\)\(=6.10^{-18}\)\(\left(C^2\right)\) (1)
Đề cho: \(q_1+q_2=10^{-9}C\) (2)
(1), (2) -> \(\left\{{}\begin{matrix}q_1=3.10^{-9}C\\q=-2.10^{-9}C\end{matrix}\right.\)