问题
选择题
已知方程x2－5x＋2＝0的两个解分别为x1、x2，则2x1－x1x2＋2x2的值为
A．8
B．－12
C．12
D．－8
答案
答案：A
由方程可知
，
所以2x1－x1x2＋2x2=
，故选A
搜题请搜索小程序“爱下问搜题”
已知方程x2－5x＋2＝0的两个解分别为x1、x2，则2x1－x1x2＋2x2的值为
A．8
B．－12
C．12
D．－8
答案：A
由方程可知，
所以2x1－x1x2＋2x2=，故选A
| 阅读理解。 |
| There are four people in the twins' family. They are the twins, their mother and their father. The twins' names are Lucy and Lily. They are fourteen. They are in the same class in No. 3 Middle School and they are all good students. Their father Mr. King is a teacher. He's thirty-nine. He teaches English in a school near his home. Their mother, Mrs. King is a doctor. She works in a hospital. Now, they are all at home. They are very happy. |
| 1. There are ______ people in the twins' family. |
[ ] |
| A. three B. four C. five D. six |
| 2. Mr. King is a ______. |
[ ] |
| A. worker B. teacher C. doctor D. student |
| 3. Mrs. King works ______. |
[ ] |
| A. in a school B. in a factory C. in a hospital D. at home |
| 4. How old is Mrs. King? |
[ ] |
| A. Thirty. B. Thirty-nine. C. Thirty-two. D. We don't know. |
| 5. The twins are in ______ Middle School. |
[ ] |
| A. number one B. number two C. number three D. number four |