Hey there, Your answer wold be 1.36 newtons rounded to 1.4 newton. This is how!
force = k (q1 * q2) / r^2
= (9.0 × 10^9 Nm^2/C^2) [(7.1 × 10^-6 C) (6.9 × 10^-6 C)] / (5.7 × 10^-1 m)^2
= [ 9.0 × 7.1 × 6.9 / (5.7)^2 ] × 10^-1 N
= 13.6 × 10^-1 N
= 1.36 N
ANSWER-1.4
HOPE I HELPED!!!!!!!!!!