Question

calculate the electric potential at a point P, a distance of 1m from either two charges of +10uC and -5uC which are 10cm apart. Calculate also the potential energy of a +2uC charge placed at a point,P

Answer 1

The nice thing about potentials is that they add (as scalars, not vectors).
Therefore if you need the potential due to two different charges,
each is k Q/R
so k (10*10^-6)/1 - k (5*10^-6)/1

then for part B multiply the potential, which is potential energy per unit charge by the charge 2*10^-6

Answer 2

Calculate the electric potential at a point P a distance of 1 m from either two charges 0f + 10μC
and -5μC which are 10 cm apart. Calculate also the potential energy of a + 2μC charge placed at
point P.