题目内容
Suppose both a and b are integer．As （a-2b）（8-a）=1，then a+b=
10
10
or
14
14
分析：由a，b都是整数，得出（a-2b）和（8-a）也是整数，而乘积为1，可以得出两个因数同为1或-1，由此求得a、b的值，问题得以解决．
解答：解：因为a，b 都是整数，所以a-2b 8-a也是整数，
因为1只能分解为1×1或（-1）×（-1），
所以①a-2b=1，8-a=1，此时a=7，b=3；
②a-2b=-1，8-a=-1，此时a=9，b=5；
因此a+b=10或a+b=14．
故答案为10或14．
因为1只能分解为1×1或（-1）×（-1），
所以①a-2b=1，8-a=1，此时a=7，b=3；
②a-2b=-1，8-a=-1，此时a=9，b=5；
因此a+b=10或a+b=14．
故答案为10或14．
点评：解答此题的关键抓住整数的性质，再把1分解为两个整数的乘积，进一步分析解决问题．
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Suppose that in Fig.2，the length of side of square ABCD is 1，E and F are mid-points of CD and AD respectively，GE and CF intersect at a point P．Then the length of line segment CP isAmerica is a mobile society. Friendships between Americans can be close and real, yet disappear soon. They don ’t feel hurt. If the same two people meet again, even years later, they pick up the friendship .This can be quite difficult for us Chinese to understand .Friendships between us develop more slowly but may become lifelong feelings, extending（延伸）deeply into both families.
There is another difficult point for us to understand . Although Americans treat friends warmly in their personal everyday lives, they don’t show their politeness to them if it requires a great deal of time. But in China ,we are usually generous with our time. We, as hosts, will appear at an airport even in the middle of the night to meet a friend. We may take days off from our work to act as guides to our friends .It is opposite in America , Americans can not manage the time to do a great deal with a visitor outside their daily plans. They will probably expect the visitors to get themselves from the airport to the hotels. And they expect the visitors will phone them from there. Once the visitors arrive at their homes , the welcome will be full , warm and real. For Americans , it is often considered more friendly to invite a friend to their homes than to restaurants, except for business matters. Americans are ready to receive us foreigners at their homes, share their holidays, and their home life. So accept their hospitality（好客）at home and enjoy your visit in America!
【小题1】The underlined phrase “pick up” in Paragraph 1 may mean “_______”.
| A．keep out | B．give up | C．pay no attention to | D．continue |
| A．Treating friends at home. |
| B．Taking days off to be with friends. |
| C．Meeting friends at the airport at midnight. |
| D．Sharing everything they have. |
| A．Americans are always generous with their time. |
| B．Americans don’t feel hurt if their friendships disappear soon. |
| C．Chinese friendships develop more slowly but will never disappear. |
| D．Chinese friendships are more sincere than American friendships. |
eger．As(a－2b)(8－a)=1，then