#lang racket
(define (quad coeffs)
  (let ((a (first coeffs))
        (b (second coeffs))
        (c (third coeffs)))
    (let ((root (sqrt (- (* b b)(* 4 a c))))
          (2a (* 2.0 a)))
      (list (/ (+ (- b) root) 2a)
            (/ (- (- b) root) 2a))
     )
 ))