# 解一元二次方程
import math
sqrt = math.sqrt

def quadratic(a,b,c):
    delta = b*b - 4*a*c
    if a==0:
        return 'Not a required equition.'
    elif delta==0:
        return -b/(2*a)
    elif delta<0:
        return 'No roots.'
    else:
        return (-b+sqrt(delta))/(2*a),(-b-sqrt(delta))/(2*a)

print(quadratic(2, 3, 1))
print(quadratic(1,3,-4))

Results: (-0.5, -1.0) (1.0, -4.0) [Finished in 0.4s]