某种型号的电脑,原售价7200元/台,经连续两次降价后,现售价为4608元/台,则平均每次降价的百分率为 .
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(-1)2n =______;(-1)2n+1 =________;
(-0.1)3=_______;
(-5) 2 =________;
(-3)3 =__________;