def solve(*s):
sp = []
if len(s) == 0 or len(s) > 3:
return 'None'
if s[0] == 0 and s[1] == 0 and s[1] == 0:
sp.append("all")
return sp
elif s[0] == 0 and s[1] == 0:
return []
elif s[2] == 0:
sp.append(0)
sp.append((-1 * s[1]) / s[0])
return sp
elif s[0] == 0:
sp.append(-s[2] / s[1])
return sp
else:
d = s[1] ** 2 - 4 * s[0] * s[2]
if d > 0:
sp.append((-s[1] + d ** 0.5) / (2 * s[0]))
sp.append((-s[1] - d ** 0.5) / (2 * s[0]))
return sp
if d == 0:
sp.append(-s[1] / (2 * s[0]))
return sp
if d < 0:
return sp
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