Python编程实践：求一个二次方程的根

import math
a = float(input("请输入a的值："))
b = float(input("请输入b的值："))
c = float(input("请输入c的值："))
if a != 0:
    delta = b**2-4*a*c
    if delta < 0:
        print("无根")
    elif delta == 0:
        s = -b/(2*a)
        print("唯一根x=",s)
    else :
        root = math.sqrt(delta)
        x1 = (-b+root)/(2*a)
        x2 = (-b-root)/(2*a)
        print("x1=",x1,"\t","x2=",x2)