Please solve it with the step

2. There are four particles each located at the corner of a square of edge length 10 cm. The particles have charges q1 = + 20.0 nC, q2 = - 30.0 nc, q3 = + 30.0 nC, and q4 = - 20.0 nC. What net electric field do the particles produce at the square's center (magnitude and direction). q1 = upper left corner of the square q4 = lower left corner of the square q2 = upper right corner of the square q3 = lower right corner of the square