A point charge q₁ = - 2.00 nC is at the origin, a second point charge q₂ = + 4.00 nC is on the x axis at x = 0.800 m, and a third point charge q₃ = - 6.00 nC is at x = 1.20 m.

a) Find the magnitude and direction of the electric field at x = 0.500 m. b) Find the force (magnitude and direction) on a charge of +1.00 nC placed at x = 0.500 m.

k = 8.99 10⁹ Nm²/C²

Express your answer with the appropriate units.