I. Fill in the blanks (3 points for each question, ***24 points)

1. The two sticks are 5cm or 7cm respectively. Choose the third stick and nail them into a triangle. If the length of the third stick is even, what is the value of the third stick? .

2.？ Is it a system of equations? The solution of, then (a+b)? The value of (a-b) is.

3. In China's stock market transactions, it is stipulated that 7.5% of the transaction price should be paid for each transaction. An investor buys a stock 1000 shares at the price of10 yuan per share, and when the stock rises to 12 yuan, all of them are sold, then the investor's actual profit is RMB.

4. As shown in the figure, in △ABC, DE is the middle vertical line of AC, AE=2.5cm,? The circumference of △ABD is 9cm, so what is the circumference of △ABC? .

5. What is the reflection of the license plate in the water? ,? Then the license plate number is.

6. For internal calls with numbers 1, 2 and 3, please call three of them at will. * * *? Different possibilities.

7. Given that two sides of a triangle are 3cm and 7cm respectively, and the length of the third side is even, what is the circumference of the triangle? .

8. The sides of a triangle are all positive integers, and the perimeter is equal to 15. Do you have such a triangle? individual

Second, multiple-choice questions (2 points for each question, *** 16 points)

1. If 5x3m-2n-2yn-m+1= 0 is a binary linear equation, then the values of m and n are () respectively.

A.2，3B.2， 1？ C.- 1，2？ D.3,4

2. Three sets of transformations between the following two diagrams belong to ()

A. Translation, rotation and rotation B. Translation, axial symmetry and axial symmetry

C. Translation, axis symmetry and rotation D. Translation, rotation and axis symmetry

There are 25 boys and 24 girls in Class 1, Grade 7 in a school. If you choose a person, the probability of choosing a boy is ().

A.0B？ c？ D.

4. As shown in the figure, after cutting off the dotted lines in the squares marked with A, B, C and D, four groups of graphs marked with P, Q, H and L are obtained. It is judged according to "which square can get the corresponding relationship of that figure after being cut off", so the wrong one in the following four conclusions is ().

5. The following statement is true ()

(1) "What is the probability of touching the red ball every time you touch it? It means that if you touch the red ball six times as required, you will touch the red ball once;

2 in the formula? In, p cannot be negative;

③ In equation (1+x2)0= 1, it holds when x takes any value;

(4) The size of probability refers to the possibility of an event, so it is uncertain whether the event will happen, so learning probability is of little help to real life.

A. 1 B.2？ C.3 D.4？

6. In △ABC and △A? b？ c？ China people, A: AB=A? b？ ; B: BC=B？ c？ ; C: AC=A？ c？ ; Ding ∠A=∠A? ; ? E: ∠B=∠B？ ; F: ∠C=∠C？ . Can't guarantee △ ABC△ A? b？ c？ The condition of establishment is ()

A.A，B，C，B，A，B，E，C，E？ d . B . E . E

7.？ Of the three internal angles of a triangle ()

A. at least one of them is equal to 900B? At least one is greater than 900.

C. maybe only one is smaller than 900D? It can't all be below 900.

8.a, B and C are three sides of △ABC, and a2+2ab=c2+2bc, then △ABC must be ().

A. equilateral triangle B. isosceles triangle C. equilateral triangle D. right triangle

Iii. Answering questions (***56 points)

1. Solve the equation (12 points)

( 1)(2)(3)?

2. It is known that the perimeter of △ABC is 18, a+b = 2c, and a-b =? , find the length of three sides A, B and C (6 points)

As shown in the figure, it is a turntable, which is divided into eight equal sectors. Please draw some sectors in the turntable into strips and meshes, so that the turntable can rotate freely. What is the probability that the pointer will fall in the bar area when it stops? What is the probability of falling into the network area? (6 points)

4. In trapezoidal ABCD, AD//BC, AB=CD, draw the line segment after translating the CD. The translation direction is the direction of ray DA, and the translation distance is the length of AD. After translation, the CD spans BC to E, so the writing method. What conclusion can be drawn from the translated picture? Please explain the reason. (7 points)

5. As shown, in △ABC, ∠A=α,? △ABC's internal bisector and external bisector intersect at point P, and ∠P=β. Try to find the relationship between α and β in the picture below, and choose one to explain it. (8 points)

6. There is a beacon B in the river. In order to know the distance from the navigation mark B to the opposite bank A, Wang Hui came up with a measuring method (assuming that this side of the river is flat). In order to know the distance from the navigation mark B to the opposite bank A, he determined a point C by the river, and made three points A, B and C into a straight line. Then he took two points P and D on the vertical line of AC, making CP=DP. At this moment, he

(1) Draw the measurement schematic diagram;

(2) Write the reasons for this measurement scheme. (8 points)

7. A milk processing factory has 9 tons of fresh milk. If it sells fresh milk directly in the market, it can make a profit of 500 yuan per ton; When yogurt is sold, the profit per ton can be 1200 yuan; Made into milk tablets for sale, the profit per ton can reach 2000 yuan. The production capacity of this factory is: if it is made into yogurt, it can process 3 tons a day; The made milk tablet can be processed 1 ton; Due to personnel constraints, the two treatment methods cannot be carried out at the same time. Due to the influence of temperature, all milk must be sold or processed within 4 days. Therefore, the processing plant has designed two schemes:

Option 1: Make as many pieces of milk as possible and sell the rest directly.

Scheme 2: One part is made into milk slices, and the rest is made into yogurt for sale, which is guaranteed to be completed in 4 days.

Which scheme do you think is more profitable? Why? (9 points)

Reference answer