问题
填空题
已知代数式x2+x+3的值是8，那么代数式9-2x2-2x的值是______．
答案
∵x2+x+3的值是8，即x2+x+3=8，x2+x=5，
∴9-2x2-2x，
=9-2（x2+x），
=9-2×5，
=-1．
故答案为：-1．
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已知代数式x2+x+3的值是8，那么代数式9-2x2-2x的值是______．
∵x2+x+3的值是8，即x2+x+3=8，x2+x=5，
∴9-2x2-2x，
=9-2（x2+x），
=9-2×5，
=-1．
故答案为：-1．
| 阅读短文，选出正确答案。 | |
very big. Where's his mother's car? It's over there. It's behind the red car. It's blue. | |
| 1. What's in the street? | |
[ ] | |
| A. Two cars. B. Four cars. C. Three cars. | |
| 2. Who has the black car? | |
[ ] | |
| A. Jim's father. B. Jim. C. Jim's brother. | |
| 3. Whose car is blue? | |
[ ] | |
| A. Jim's. B. Jim's father's. C. Jim's mother's. | |
4. Where is Jim's mother's car? | |
[ ] | |
| A. It's near the street. B. It's behind the red car. C. I don't know. |