在横线上填:“+”号或“-”号,使等式成立:(a-b)3=______(b-a)3.
(a-b)3=[-(b-a)]3=(-1)3•(b-a)3=-(b-a)3.
故答案为:-.
A.电源电压
B.灯L1两端的电压
C.灯L2两端的电压
D.灯L1与L2两端的电压
Tim’s always busy _______ One thing or another and you never find him at play. [A] in [B] with [C] of