08/10/07 22:48:00
>>892
(-1) + (-1)×(-1)
= 1×(-1) + (-1)×(-1) [乗法3]
= (1 + (-1))×(-1) [分配]
= 0×(-1) [加法4]
= 0 + 0×(-1) [加法3]
= (0×(-1) + (-(0×(-1)))) + 0×(-1) [加法4]
= ((-(0×(-1))) + 0×(-1)) + 0×(-1) [加法1]
= (-(0×(-1)) + (0×(-1)) + 0×(-1)) [加法2]
= (-(0×(-1)) + (0 + 0)×(-1)) [分配]
= (-(0×(-1)) + 0×(-1) [加法3]
= 0×(-1) + (-(0×(-1)) [加法1]
= 0 [加法4]
= 1 + (-1) [加法4]
= (-1) + 1 [加法1]
∴ (-1)×(-1) = 1 [加法5]