Four Point Charges of Magnitude 6

Essay

Four point charges of magnitude 6.00 μC and of varying signs are placed at the corners of a square 2.00 m on each side,as shown in the figure.(k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)
(a)What is the electric potential (relative to infinity)at the center of this square due to these charges?
(b)What is the magnitude of the electric field due to these charges at the center of the square?