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

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.