For real numbers ａ and b， define a＄b＝（a－b）
. What is （x－y）＄（y－x）？______
一种专门侵占内存的计算机病毒，开机时占据内存2KB，然后每3分钟自身复制一次，复制后所占内存是原来的2倍，那么开机后经过______分钟，该病毒占据64MB内存。
已知幂函数y＝f（x）的图象过点
，则f（2）＝_______
函数y＝
的定义域是________
27
＋lg4＋2lg5＝__________
A semipro baseball league has teams with 21 players each. League rules state that a player must be paid at least ＄15，000，and that the total of all players’ salaries for each team cannot exceed ＄700，000. What is the maximum possible salary，in dollars，for a single player？
A. 270，000 B. 385，000 C. 400，000 D. 430，000 E.700，000
