The sum of an 84-number series is -7,980. What is the sum of the first and last numbers?

Alicia puts $400 in a bank account. each year the account earns 5% simple interest. how much money will be in her bank account in six months?

Solve the system of equations. x=-2y+1 and x+2y=9. show work

The room above is shaped like a rectangle anthe room above is shaped like a rectangle and has a perimeter of 34 feet. if the room is 11 feet long, how wide is it?