问题
解答题
解方程组：
|
答案
3x+3y=7(1) 6x-2y=-1(2)
把①式两边乘2，得6x+6y=14③，
③-②得8y=15，
解得y=
，15 8
把y=
代入①得3x+15 8
=7，45 8
解得x=
，11 24
所以原方程组的解为
．x= 11 24 y= 15 8
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解方程组：
|
3x+3y=7(1) 6x-2y=-1(2)
把①式两边乘2，得6x+6y=14③，
③-②得8y=15，
解得y=
，15 8
把y=
代入①得3x+15 8
=7，45 8
解得x=
，11 24
所以原方程组的解为
．x= 11 24 y= 15 8
| 完形填空。 | |||
| Have you ever seen the new way of __1__ fresh water? Here is an example. First, people make some long ponds (池塘) which are about half a meter __2__. Then they __3__ a cover (盖子) over each pond. The cover is made of glass that you can see through. At night, sea water __4__ into the ponds. The __5__ day, the __6__ sun shines through the covers. The sun light __7__ the water into vapor (水蒸气) that goes up from the __8__. As it goes up, the vapor becomes mist (薄雾).On the inside of each cover the little drops of mist run together to make big drops. People then __9__ these big drops through a special conduit (管道). Then the ponds are ready for the next day's work. __10__ we know, the covers and other parts of the ponds cost very little. Sea water and the sun cost nothing. So this new way of getting fresh water seems wonderful. | |||
| ( ) 1. A. taking ( ) 2. A. deep ( ) 3. A. raise ( ) 4. A. takes ( ) 5. A. last ( ) 6. A. beautiful ( ) 7. A. turns ( ) 8. A. ponds ( ) 9. A. buy ( ) 10. A. Which | B. making B. thick B. tie B. is taken B. third B. nice B. brings B. covers B. collect B. Since | C. getting C. high C. fetch C. is taking C. first C. hot C. becomes C. cups C. drink C. For | D. bringing D. wide D. put D. taken D. next D. Warm D. gets D. glass D. clean D. As |