2. It is known that (3m- 1)x 2 n+ 1+9 = 0 is a linear equation about X, so the conditions that M and N should meet are m,

n = .

3. When the value of x is -3, the algebraic expression -3x 2 +a x-7 is -25, and when x=- 1, the algebraic expression is.

4. The positive integer solution of equation 2x+y = 5 is.

5. Given that the solution of the equation is also the solution of the equation 3x-2y = 0, then k =.

6. If (2x-y) 2 are opposite to each other, then (x-y) 2005 =.

7. The picture shows the price tag of a shampoo in Wenjie Supermarket, so the original price of this shampoo is.

7 questions 15 questions

8. If there is a two-digit number, the sum of the ten-digit number and the one-digit number is equal to 9, and the ten-digit number is 1 more than three times that of the one-digit number, then the two-digit number is.

9. According to the national regulations, the deposit interest tax = interest ×20%, and the annual interest rate of one-year fixed deposit in the bank is 1.98%. Xiao Ming has a year's deposit. If he takes it all out when it is due, he can get it back 12 19 yuan. If Xiaoming's deposit is X yuan, according to the meaning of the question, the equation can be listed as.

10, the perimeter of a triangle is 15cm, and both sides are equal to twice the third side, so the length of the shortest side in this triangle is cm.

If the two sides of an isosceles triangle are 1 1 and 12cm and 7cm respectively, the length of its third side is cm.

12, as shown in the figure, ∠A=280, ∠B=420, ∠DFE= 1300, then ∠C= degrees.

13. It is known that the circumference of a triangle is even, and the three sides are 2, 3 and x respectively, so the value of x is.

14 in a polygon with equal internal angles, an internal angle is four times that of an external angle, the degree of each internal angle of this polygon is, and the number of sides of this polygon is.

15. After completing the door frame, the master often sticks two diagonal battens (AB and CD in the figure) to prevent deformation. The mathematical reason for this is that.

Second, choose one carefully: (3 points for each question, *** 15 points)

16, the following statement is true ()

A. A linear equation with one variable must have only one solution; B the binary linear equation x+y=2 has countless solutions;

C. Equation 2x=3x has no solution; D. the value of the unknown quantity in the equation is the solution of the equation.

17, the following statement is wrong ()

A. The midline, angle bisector and height line of a triangle are all line segments;

B the sum of the external angles of any triangle is 3600;

C. Triangles can be divided into equilateral triangles and isosceles triangles according to their sides;

D. One external angle of a triangle is greater than any internal angle.

18. In △ABC, ∠ A-∠ B = 900, then △ABC is a () triangle.

A. acute triangle; B. right triangle; C. obtuse triangle; D. not sure

19, if you want to restore the original price of a commodity after a price increase of 20%, the percentage that must be reduced is about ().

a . 17%； b . 18%； c . 19%； D. 20% .

20. Given that x+4y-3z = 0 and 4x-5y+2z = 0, then x: y: z is ().

a . 1:2:3； b . 1:3:2； c . 2: 1:3； D. 3: 1:2

Third, carefully calculate:

2 1. Solve the following equations (groups): (5 points for each question, ***20 points)

( 1) ; (2) 3x +。

(3) (4)

Fourth, think about it carefully: (the total score is 3 1 minute)

22. (6 points in this question) As shown in the figure, in △ABC, D and E are points on the side of BC and AB, respectively, and AD divides ∠EDC equally. Try to explain the reason of ∠ bed > ∠ B.

23. (8 points in this question) Party A and Party B travel from Party A, Party B to Party C respectively. It takes 3 hours for Party A to travel from Party A to Party C, and 2 hours and 40 minutes for Party B to travel from Party B to Party C. It is known that the distance from Party A to Party C is farther than that from Party B to Party C 10 km, and Party A walks 3 km more than Party B every hour.

(1) Find the distance between a and c.

(2) Assuming that AC, BC and AB are straight, try to determine the range of distance d between A and B. 。

24. (8 points in this question) In order to improve the greening level and beautify the environment, the school is going to divide a rectangular grassland with a circumference of 76m into 9 small rectangles with equal length and width (as shown in the figure) and plant various flowers. According to the market forecast, the greening cost per square meter is about 108 yuan.

(1) Find the length and width of each small rectangle.

(2) Please calculate how much money is expected to be invested to complete this greening project? Seek adoption