I need help please (22 points or more in the future)

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible

Find the rate of change for the situation.you run 7 miles in one hour and 21 miles in three hours.

Solve the equation for x. 50(4x + 12) = 200