Two point charges are placed on the x-axis as follows: Charge q1 = +4.00 nC is located at x = 0.200 m and charge q2 = +5.00 nC is at x = -0.300 m. What are the magnitude and direction of the total force exerted by these two charges on a negative point charge q3 = -6.00 nC that is placed at the origin?