I need help finding the rules

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters.

You are designing a rectangular pet pen for your new baby puppy. you have 30 feet of fencing you would like the fencing to be 6 1/3 feet longer than the width

You borrow $25,000 to buy a boat. the simple interest rate is 4%. you pay the loan off after 10 years. what is the total amount you paid for the loan?