[tex]dane:\\q_1 = +3 \ C\\q_2 = -6 \ C\\r = 9 \ cm = 0,09 \ m = 9\cdot10^{-2} \ m\\k = 9\cdot10^{9}\frac{Nm^{2}}{C^{2}}\\szukane:\\F = ?\\\\Rozwiazanie\\\\F = k\cdot\frac{|q_1\cdot q_2|}{r^{2}}\\\\F = 9\cdot10^{9}\frac{Nm^{2}}{C^{2}}\cdot\frac{|3 \ C\cdot(-6 \ C)|}{(9\cdot10^{-2} \ m)^{2}}\\\\F = 9\cdot10^{9}\frac{Nm^{2}}{C^{2}} \cdot\frac{18 \ C^{2}}{81\cdot10^{-4} \ m^{2}}\\\\\underline{F = 2\cdot10^{13} \ N}[/tex]
