A 4 nC charge is fixed at x = 0 m. A 12 nC charge is fixed at x = 3.5 m. (Note that 1 nC= 10-9 C) Calculate the

electric field at x = 1.3 due to these charges, in N/C. Use k = 9x 109 N m2 / C2. Your answer could be positive or negative.