Knox ran 5 1/4 miles in 6/7 of an hour. How many miles can Knox run in one hour?

Can someone answer these problems for me

What is the frequency of the sinusoidal graph?

Desmond wants to sell his car that he paid $8,000 for 2 years ago. the car depreciated, or decreased in value, at a constant rate each month over a 2-year period. if x represents the monthly depreciation amount, which expression shows how much desmond can sell his car for today? \ 8,000 + 24x 8,000 - 24x 8,000 + 2x 8,000 - 2x