3x power of 2+ 5x+2=0what does x equal

Ms. ford's kitchen is in the shape of a rectangle with a width of 12.25 feet. she is buying a wallpaper border to go on all of her kitchen walls. she wants to buy 5 extra feet of the border to be sure she has enough. she buys 62.5 feet of the border. what is the length of ms. ford's kitchen? explain how you can find your answer.