import math

def quadratic(a, b, c):
    for x in (a,b,c):
        if not isinstance(x,(int,float)):
            raise TypeError("类型错误！")
    if a==0:
        return 0-c/b
    d=math.sqrt(b*b*1.0-4*a*c)
    return (0-b+d)/(a*2),(0-b-d)/(a*2)