Oceanside Bike Rental Shop charges an initial fee of 15 dollar plus 7 dollars an hour for renting a bike. Joan paid 57 dollars to rent a bike. How many hours did she pay to have the bike checked out?

An advertising firm has an old computer that can prepare a whole mailing in 6 hours. with the of newer model the job is complete in 2 hours. how long would it take the newer model to do the job alone?

Which conjunction is disjunction is equivalent to the given absolute value inequality? |x+2|< 18

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle