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打开数学,就觉得很难: a certain theater has 100 balcony seats. for every $2 increase in the price of a balcony seat above $10, 5 fewer seats will be sold. if all the balcony seats are sold when the price of each seat is $10, which of the following could be the price of a balcony seat if the revenue from the sale of balcony seats is $ 1,360? 解答是这样的:(10+2x)(100-5x)=1360 x1=3, x2=12 题目说,if all the balcony seats are sold when the price of each seat is $10,不是说全部都卖10块钱? |