GRE
$$ (-1)^x$$
$$ (-1)^{-x}$$
The number of copies of Magazine X that were sold last month at the subscription price
Twice the number of copies of Magazine X that were sold last month at the cover price
RT
ST
The percent increase in the dollar value of the antique from 1984 to 1988
$$54%$$
$$s+t$$
$$b$$
25000 +道题目
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