;; Finally use the data:
(let ((x #2A((0 1 2 3 4 5 6 7 8 9 10)))
      (y #2A((1 6 17 34 57 86 121 162 209 262 321))))
    (polyfit x y 2))

#2A((0.999999966345088) (2.000000015144699) (2.99999999879804))