Three charged particles form a triangle: particle 1 with charge Q1 = 80.0nC is at xy coordinates (0, 3.00 mm), particle 2 with charge Q2 is at (0, -3.00mm), and particle 3 with charge q = 18.0nC is at (4.00 mm, 0). In unit-vector notation, what is the electrostatic force on particle 3 due to the other two particles if Q2 equal to

(a) 80.0nC and

(b) – 80.0nC?