python函数

import math
def rootOfEquation(a, b, c):
    if b * b - 4 * a * c < 0:
        return []
    if b * b - 4 * a * c == 0:
        return [-b / (2.0 * a)]

    delta = math.sqrt(b*b-4*a*c)
    return sorted([(-b-delta)/2.0*a, (-b+delta)/(2.0*a)])