Which ordered pair is a solution to the equation 3x-3y=21

There is a line with slope 1/a going through the point (a, a²). find the equation of the line perpendicular to this line at this point. (don’t let this problem intimidate you! solve the problem as you would if i’d given you specific values. just use variables instead.)

The variable in a relation who’s value depends on the value of the independent variable is called what?

For what value of (y) is 3^3/3^y =1/9