import math

def quadratic(a, b, c):

    x1=((-b+math.sqrt(b**2-4*a*c))/(2*a))

    x2=((-b-math.sqrt(b**2-4*a*c))/(2*a))

    return x1,x2

# 测试:

print('quadratic(2, 3, 1) =', quadratic(2, 3, 1))

print('quadratic(1, 3, -4) =', quadratic(1, 3, -4))

if quadratic(2, 3, 1) != (-0.5, -1.0):

    print('测试失败')

elif quadratic(1, 3, -4) != (1.0, -4.0):

    print('测试失败')

else:

    print('测试成功')