问题
解答题
已知：x+y=1，xy=-3，求下列各式的值：
（1）x2+y2；
（2）x3+y3；
（3）x5y+xy5．
答案
（1）∵x+y=1，xy=-3，
∴原式=（x+y）2-2xy=1+6=7；
（2）原式=（x+y）（x2-xy+y2）=7+3=10；
（3）原式=xy（x4+y4）=xy[（x2+y2）2-2x2y2]=-93．
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已知：x+y=1，xy=-3，求下列各式的值：
（1）x2+y2；
（2）x3+y3；
（3）x5y+xy5．
（1）∵x+y=1，xy=-3，
∴原式=（x+y）2-2xy=1+6=7；
（2）原式=（x+y）（x2-xy+y2）=7+3=10；
（3）原式=xy（x4+y4）=xy[（x2+y2）2-2x2y2]=-93．
In the following passage, there are 20 blanks representing words that are missing from the context. Below the passage, each blank has 4 choices marked by letter A, B, C and D respectively. There is only ONE right answer. Blacken the corresponding letter as required on your Machine-scoring ANSWER SHEET.
| How many of us would temp for three years while we waited for the perfect job Not many of us, perhaps. But Wentworth Miller, the "Prison Break" star, said he chose to wait even longer time (91) he found the right job. "Actually I think it might have been three or four years until I was lucky enough to get guest (92) on TV shows," said Miller, 34, who rose to international stardom (93) to "Prison Break" in 2006. That kind of patience and p will was portrayed in "Prison Break". Miller (94) engineering wizard Michael Scofield, who tries everything to break out of a Chicago (95) with his brother. Miller said he was fond of his character, (97) he said "exists in shades of grey". Miller comes from a (97) of teachers. He said he didn’t seem fated for a career in the arts, (98) his passion for acting. After (99) from Princeton with an English degree, he moved (100) his parents’ request to Los Angeles to look for a stable life. He started (101) in a little company that made television movies. This (102) simply faxing, filing, walking the boss’ dog and going to the store for the boss’ lunch. Every weekend during the summer, Miller (103) go to the office (104) he didn’t have air-conditioning. "I would hang (105) in the conference room and set up camp and rob the company kitchen," recalled Miller. (106) , Miller realized he still had questions about his choice. He decided to quit. But the boss said he was making a mistake and offered him a well-paid assistant position. "I eventually (107) that if I did the corporate job, it would be great if I was successful, but I would always wonder about the (108) . If I did the acting and was successful, I would never wonder (109) that job," he explained. He quit and temped (110) many people in the entertainment industry. |
A．However
B．Therefore
C．Thereby
D．Thereupon