This means that (x-6)(x+2) = f(x) is the equation for the parabola due to that if you plug these in, when x=6 and x=-2 then y=0. Expanding it, we get x^2+2x-6x-12=x^2-4x-12. Since the x coordinate of the vertex is -b/2a, it's 4/2=2
22 because 6 inches on top and bottom means you need 12 inchesw each drape and you have 4 drapes so 48 inches therefor rounding that you get 1 yard each added onto the 8 feet and 5 feet for each drape.