Need help with practice problem!

Q2) Two point charges are located on the x axis. One charge q1 = 5 \"C is at x = 30.0 cm, and the other charge qz = 10 \"C is located at x = 40.0 cm. (a) Calculate the electric eld at the origin due to the two charges. (b) Calculate the electric eld on the y axis at y = 40 cm. due to the two charges (in unit vector notation (i, j, k)). (c) Calculate the electric force on a 3.0 yC charge placed on the y axis at y = 40 cm