What must be the distance between point charge q1 26.0 mC and point charge q2 47.0 mC for the electrostatic force between them to have a magnitude of 5.70 N?

(Where FF is the electrostatic force, kk is Coulomb’s constant, q_1q​1​​ is the charge of the first particle, q_2q​2​​ is the charge of the second particle, and rr is the distance between the two charges)

(isolate for r)

5.7r^2=(8.99\times 10^9)(26\times 10^{-6})(47\times 10^{-6})5.7r​2​​=(8.99×10​9​​)(26×10​−6​​)(47×10​−6​​)

r^2=1.9273298r​2​​=1.9273298

r=\sqrt{1.9273298}=1.39r=√​1.9273298​​​=1.39 m