import math

def quadratic(a, b, c):

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

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

return x1, x2

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')