Solve these equasions much appreciated

Find the domain of the function  [tex]f(x) = \sqrt{3x - 7} [/tex]in interval form, the domain of f is what? in advance.

Of the 304 people who attended a school play, 5/8 were students. how many of the people who attended were students.

Agrid shows the positions of a subway stop and your house. the subway stop is located at (-5,2) and your house is located at (-9,9). what is the distance, to the nearest unit, between your house and the subway stop?