A.3 B. 4 C. 5 D.6
2.if a
A. first quadrant B. second quadrant C. third quadrant D. fourth quadrant
3. There are four pieces of wood with lengths of 4cm, 7cm, 9cm, 1 1cm. If three pieces are selected to form a triangle, the selection method is ().
1。
4. The solution of the linear inequality group is ()
A.x & gt-3 b . x & lt； 2 C.25 Among the following propositions, the correct number of propositions is ().
On the same plane, two disjoint line segments are called parallel lines. Two disjoint lines are called parallel lines.
③ Later, there is only one straight line parallel to the known straight line ④ Two straight lines perpendicular to the same straight line are parallel.
A.0B. 1 C.2 D.3。
6. If every interior angle of a polygon is equal to 144o, then the sum of its interior angles is ().
a 1260 o b 1440 o c 1620 o d 1800 o
7. A car was driving on a straight road and turned two corners, still in the same direction.
Parallel forward, then the angle of these two turns is ()
A. Turn right 60o for the first time,120o; The second time to the left;
B. Turn left for the first time 120o and turn right for the second time120o;
C. Turn right 60o for the first time and 60o for the second time;
D. Turn left for 60o for the first time and turn left for the second time 120o.
8. As shown in figure 1, lines A and B are cut by lines C and D, and it cannot be judged that a‖b is () under the following conditions.
A.∠ 1=∠2 B. ∠5=∠7 C. ∠4=∠6 D. a⊥d、d⊥b
7. Let "●", ▲ "and ■" represent three different objects and weigh them twice with a current balance, as shown in Figure 2. Then, these three objects are arranged as () in descending order of mass.
A.■●▲ B. ■▲● C. ▲●■ D. ▲■●
10. There are 20 multiple-choice questions in the intelligence test. The grading standard is: 1 5 points for the question, 2 points for the wrong 1 question, no points or points for not answering the question. Xiao Ming has two unanswered questions. If he answers at least a few questions correctly, the total score will not be lower than 60 points. Then the number of questions that Xiao Ming answered correctly is at least ().
A.7 Questions B.8, C.9 and D. 10
Fill in the blanks: (3 points for each small question, ***24 points)
1 1. Calculation -(-3)+-=.
12. A triangular piece of paper ABC, ∠A=55o, ∠B=65o. Now fold the corner of the paper.
Let point C fall on ABC, as shown in Figure 3. If ∠ 1=30o, ∠ 2 =. a.
13. If y=++2, the square root of 3x+4y- 1 is.
14. Give you a pair of numerical values, please write a binary linear equation group.
Let this pair of numbers be the solution satisfying this system of equations.
15. As shown in Figure 4, in Δ ABC, AB = 2.5 cm and BC = 4 cm, then Δ ABC's
The ratio of high AD to CE is.
16. Can any quadrilateral with the same shape and size be inlaid into a plane pattern? (Fill in "can" or "can't") because:
17. As shown in Figure 5, translate the right-angled trapezoidal ABCD to the trapezoidal EFGH along the AD direction.
Hg = 24m, Mg = 8m, MC = 6m, then the area of the shadow part is.
18. Observe the following equation, =2, =3,
=4, please write a list containing n (n > The equation of 2) represents the general formula of the above laws:.
Three. Problem solving: (19,20,21,22,23, 6 points, 24,25, 8 points, ***46 points)
19. Solve Equation 20. Solve inequalities and express the solution set on the number axis.
2 1. A shopping mall buys 50 pieces of goods A and B. The profit rate of each piece of goods A in 35 yuan is 20%, while that of goods B in 20 yuan is 15%, and the profit of * * * is 278 yuan. How many pieces of goods A and B were purchased respectively?
22. As shown in Figure 6, the quadrilateral ABCD is in a plane rectangular coordinate system. Answer (2, 2).
(1) Write the coordinates of b, c and d respectively.
(2) Find the area of quadrilateral ABCD. (Keep two significant figures)
23. As shown in Figure 7, in Δ ABC, ∠A=40o, ∠ ABC =10o, CE divided by ∠ACB, CD⊥AB in D, DF⊥CE. Find ∠CDF.
24. A company divided its soldiers into eight groups in one mission. If the number of soldiers assigned to each group is more than the predetermined number 1, the total number of soldiers will exceed 100. If the number of soldiers assigned to each group is less than 1, the total number of soldiers will be less than 90. Please reserve the number of soldiers assigned to each group.
25. In order to protect the environment, an enterprise decided to buy 10 sewage treatment equipment. There are two types of equipment, A and B. The price of each equipment, monthly sewage treatment capacity and annual consumption fee are as follows:
According to the budget, the funds used by enterprises to purchase equipment are not higher than 6.5438+0.05 million yuan.
Please design several purchasing schemes for this enterprise;
If the amount of sewage produced by the enterprise is 2040 tons per month, which purchase scheme should be chosen to save money;
Under the condition of (2), if the service life of each equipment is 10 year and the sewage treatment fee of the sewage plant is per ton 10 yuan, please calculate how much RMB 10,000 yuan the enterprise can save by treating sewage by itself compared with the sewage treatment plant. (Note: Enterprise sewage treatment expenses include equipment purchase expenses and consumption expenses)