Reference answers and scoring suggestions

Note: One or several answers are given for each question in this grading standard for reference. If the candidate's answer is different from this answer, it will be graded according to the spirit of this grading standard.

A, multiple-choice questions (this question * * * has 8 small questions, each small question 3 points, ***24 points)

Title 12345678

Option b c d c a a b c

Fill in the blanks (there are 10 small questions in this big question, with 3 points for each small question and 30 points for * * *).

9. 10. 1 1. 12.9 13. 105

14.25% 15.40 16.8 17. 18.39

Third, solve the problem (this big question * * has 10 small question, ***96 points. When answering, write the necessary text description, proof process or calculus steps)

19. Solution: (1) Original formula = = 0.

(2) Original formula =

=

= .

20. Solution: Solve the inequality (1), so,

Solve inequality (2),

The solution set of the original inequality group is.

All its integer solutions are:.

2 1.( 1) 50, 5 times.

(2)

(3) (person)

A: Of the 350 ninth-grade boys in this school, about 252 can meet the standard.

22. Solution: (1) 4.

(2) Used to represent four options. (Other representations are also acceptable. )

Solution 1: The tree diagram is used to analyze as follows:

Solution 2: The tabular analysis is as follows:

Xiao Gang

Xiaoming a b c d

A(A，A)(A，B)(A，C)(A，D)

B(B，A)(B，B)(B，C)(B，D)

C (C, A) (C, B) (C, C) (C, D)

D(D，A)(D，B)(D，C)(D，D)

Xiao Ming and Xiao Gang chose the same plan.

23.( 1) proves that it is high,

It's a male side again,

It is an isosceles triangle.

(2) Solution: The point is on the bisector of the angle.

The reason for this is the following：

and

A point on the bisector of an angle.

24.( 1) A: indicates the working day of the construction team, indicating the working day of the construction team;

B: It refers to the number of meters of river regulation by the engineering team, and it refers to the number of meters of river regulation by the engineering team.

A: b:

(2) Solution: Set up two engineering teams to control the river rice and rice respectively.

Judging from the meaning of the question:

Solve the equation:

A: The two engineering teams rectified 60m and120m respectively.

25. solution: (1) in,

(2) Settings

Yes,

that is

solve

The radius of the water tank is 18.5 cm.

26. Solution: (1) Draw correctly (traces of vertical lines in line segments need to be preserved).

Straight lines and tangents.

The reason for this is the following：

Links,

Divide equally,

.

that is

The straight line passes through the outer end of the radius, which is the tangent.

(2) Settings, in,

Solve.

The required graphics area is

27. Solution: (1) The height of iron blocks B, A and B is 14cm (or when the water depth of cylinder B reaches 14cm, the iron blocks just submerged in the water, so just tell the general idea).

(2) Let the functional relationship of the line segment be

The functional relationship of is

Let the functional relationship of the line segment be

The functional relationship of is.

From the meaning of the problem, solved.

Inject water for 2 minutes, and the water depth of cylinder A and cylinder B is the same.

(3) Water is injected into cylinder B at a uniform speed from cylinder A, and the amount of water injected into cylinder B in the first 4 minutes is twice that in the last 2 minutes.

Let the difference between the bottom area of B tank and the bottom area of iron block be S, then

solve

The bottom area of the iron block is.

The volume of iron is

(4) The area of the bottom of the nail groove is

The volume of iron block is, and the bottom area of iron block is.

If the nail groove bottom area is, the water injection speed is.

Derive from the meaning of the problem

The area at the bottom of the nail groove is

28. Solution: (1)

The reason for this is the following：

As shown in figure 1,

.

(2) cm.

Vertical score, cm.

=4cm。

① The moving speed of the set point is cm/s. 。

As shown in figure 1, when, by (1).

that is

As shown in Figure 2, it is easy to know when it is appropriate.

To sum up, the point velocity is1cm/s.

②

As shown in figure 1, when,

.

As shown in Figure 2, when,,,

.

All in all,

(? ) ?

The reason for this is the following：

As shown? Extend to, manufacture, connect,?

, bisect each other, quadrilateral is parallelogram,.

, , .

Vertical division,.