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

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')