Urgent! test tomorrow! need factoring with steps or explanantion. i don't understand how you get the gcf when you have a number in front of the x^2

What is the missing constant term in the perfect square that starts with x^2 -20x

Describe what moves you could use to create the transformation of the original image shown at right

Mrs. avila is buying a wallpaper border to go on all of her kitchen walls. she wants to buy 5 extra feet of wallpaper border than she needs to be sure she has enough. she buys 55.5 feet of the border. the store owner selling the border uses the width of mrs. avila's kitchen to determine that the length of her kitchen must be 14.5 feet.