Anybody know? help is greatly appreciated!

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

Tim open up a new saving account with a $50 deposit and plant to deposit $20 per week into the same account.write an expression to represent the total amount in his savings account.