Apositive charge, q1, of 5 µc is 3 × 10–2 m west of a positive charge, q2, of 2 µc. what is the magnitude and direction of the electrical force, fe, applied by q1 on q2?

The law you need is :
lets call the constant c = 4pi*epsilon naught*r2.
where r is radius ( or seperation of the charges). epsilon naught is a constant of about 8.85*10^-12 or something like that. and 4 pi is just 4 times pi.
the actual equation is 
FORCE= (q1*q2)/c

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