particles A and B each carrying a charge of 3.0 nC are at the base corners of an equilateral triangle 2.0m on a side

a. what is the potential at the apex of the triangle

b. how much work is required to bring a positively charged particle carrying a charge of 4.0 NC from the infinity to the apex of the triangle if A and B are held fixed

c. calculate the electric potential energy for each of the two triangular charge distributions