"distance between -6C and 3C="1-(-5)=6 " m" r_1^2=6^2=36 "distance between 4C and 3C="(-2)=3 " m" r_2^2=3^2=9 "Force between -6C and 3C is attractive:" F_1=(k*(-6)*3)/36 F_1=(-18*k)/36 "F_1=-k/2 "Force between 4C and 3C is:" F_2=(k*4*3)/9 F_2=(4*k)/3 F_(3C):" Net force acting to charge of 3C" F_(3C)=(4*k)/3-k/2 F_(3C)=(8*k-3*k)/6, F_(3C)=(5*k)/6 F_(3C)=(5*9*10^9)/6 F_(3C)=7,5*10^9 " N"