What is the domain of this function

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Which is the equation of a line perpendicular to the line with the equation 3x+4y=8

If, while training for a marathon, you ran 60 miles in 2/3 months, how many miles did you run each month? (assume you ran the same amount each month) write your answer as a whole number, proper fraction, or mixed number in simplest form. you ran __ miles each month.