Solving a problem in physics section 1 paragraph 5 ele

5. Two point electric charge Q1 = 1 nC and nC Q2 = -2 are at a distance d = 10 cm from each other in the air. To determine the potential φ field intensity E, generated by the charges at a point remote from the charge Q1, a distance r1 = 9 cm, and the charge Q2 at a distance r2 = 7 cm.