import?math

def?quadratic_equation(a,?b,?c):
????t?=?b**2?-?4*a*c
????if?a?==?0?or?t?<?0:
	return?'無解'
????elif?t?==?0:
????????x1?=?-b/2*a
????????return?'有唯一解',x1
????else:
	x1?=?(-b?+?math.sqrt(t))/(2*a)
	x2?=?(-b?-?math.sqrt(t))/(2*a)
	return?x1,x2

print?quadratic_equation(2,?3,?0)
print?quadratic_equation(1,?-6,?5)

提示

if a == 0 or t < 0:
^
IndentationError: unexpected indent

看起來是正常的，把if、elif、else前的Tab換成四個空格就好了，為什么會有意外縮進產生呢？