I. Fill in the blanks (30 points)

1. When x, the score is meaningful. 2. In the function y=, the value range of the independent variable x is.

3. If there is no solution to the fractional equation about.

4. At that time, the score was 0.

5. Measured on the map with the scale of 1︰2000, the distance between AB is 5cm, so the actual situation between AB and AB is

The distance is meters.

6. About integral: =.

7. As a result of simplification.

8. The diameter of cold virus is 0.000000 12m, which is expressed by scientific notation as follows.

9. The solution of the equation is.

10. A city rebuilt a road with a total length of 1500m. The original plan was to repair the watch every day. In order to minimize the impact of construction on urban traffic, in actual construction, the road was repaired 35 meters more than originally planned, so it actually took several days to repair this road.

2. Multiple choice questions (2 1)

1 1, in the algebraic expression, the score is ().

a， 1； b，2； c，3； D. four.

12. If the score is 0, the value of x is ().

A. 1B。 - 1C。 1d . 2

13. the result of calculation is () A.B.C.D

14. If the values of x and y in the score are magnified 3 times at the same time, the values of the subsequent scores will also be magnified ().

A, expand by 3 times; B, 3 times smaller; C, remain unchanged; D, I can't be sure.

15. The calculation result is ()

A.B. C. D。

16, Xiao Mahu only got one question right in the following calculation, and the right question is ().

A, B, C, D,

17. If Party A finishes a job alone and Party B finishes it alone within b hours, it will take () hours for both parties to finish it together.

A.； b； c； D.

Three. Short answer questions (18- 19 * * 12, 20-25 * * 30, 26 questions 7)

18, calculation

19.(-) ÷ 20. Solve the equation:

2 1. Simplify first and then evaluate.

22. (In class, Miss Li asked such a question:

It is known that finding algebraic expressions is too complicated for Xiao Ming to substitute directly into calculation. Please help him solve it and write down the specific process.

Affected by many factors, the pork market price is still rising this year. According to the survey, the price of first-class pork in May this year was 0.25 times that of pork in 65438+ 10. Xiaoying's mother also bought it for 20 yuan in May.

The first-grade pork is 0.4 kg less meat per catty than the first-grade pork bought in June of 5438+ 10, so how much is it this year?

24. Before the rainstorm, a certain unit of the Armed Police Force undertook the task of strengthening the150m long river bank. After 40 meters of reinforcement, we received instructions from the superior drought and flood control headquarters to speed up the construction progress. Therefore, under the premise of ensuring the construction quality, the unit invested more troops to reinforce 15 meters every day, and it took three days to complete the task. How many meters does the army reinforce the river bank every day after receiving the instruction?

25. During the period of Spring Festival travel rush in 2008, a large-scale snowstorm occurred in southern China, which led to a power outage of a certain circuit. The local power supply bureau organized electricians to carry out emergency repair. The power supply bureau is 15km away from the emergency repair site. The emergency repair vehicle loaded with the required materials starts from the power supply bureau first. 15 minutes later, the electricians took a jeep from the same place. As a result, they arrived at the emergency repair site at the same time. The speed of the jeep is known as 1.

26. A project received bids from two teams, A and B, and it needs to pay 65,438+2,000 yuan for team A and 5,000 yuan for team B for one day of construction. According to the calculation of the bids of Team A and Team B, the project leading group has the following scheme:

(1) Team A completed the project alone as scheduled;

(2) Team B completed the project alone for 6 days longer than the specified date;

(3) If Team A and Team B work together for 3 days, the remaining projects will be completed by Team B alone.

On the premise of not delaying the construction period, which construction scheme do you think is the most economical? Please explain the reason.