People's Education Edition Junior High School Mathematics winter vacation homework
First, multiple-choice questions (this question 10 small questions, 3 points for each small question, 30 points out of * * *).
The absolute value of the reciprocal of 1. Yes ()
A: B: C:2 D:-2
In the next three years, the state will invest 850 billion yuan to help the masses? Difficult and expensive to see a doctor? problem 850 billion yuan is expressed as () by scientific notation.
A.1 billion yuan
3. If _ _ _ _ _ _ _ _ _, then all the following statements are correct ().
A.
B.
C.
D.
4. If the value of the algebraic expression is 7, then the value of the algebraic expression is equal to ()
A.2 B. 3 C.﹣2
5. observed that ship a is located at 54? At the same time, ship b is in the east of south 15? What about the direction? The size of AOB is ()
Point 69? B. 1 1 1？ C. 14 1？ D. 159？
6. Given that the equation is a one-dimensional linear equation, the solution of the equation is equal to ().
A.- 1
7. Which of the following angles () can't be made directly with a set of triangles (without other tools)?
a、45？ Angle b, 75? Angle c, 15? Angle d, 50? Angle of
8. In the following figures, which can be the flat expansion diagram of the cube is ().
9. First, a jacket is marked with a 50% increase in cost, and then sold at a 20% discount (80% of the marked price).
Leigh 28 yuan, if the cost of this jacket is X yuan, according to the meaning of the question, the equation can be obtained as ().
A.( 1+50%)x？ 80%=x-28 B.( 1+50%)x？ 80%=x+28
C.( 1+50%x)？ 80%=x-28 D.( 1+50%x)？ 80%=x+28
10. Calculate according to the following procedure:
If the input and output result is 50 1, if the input and output result is 63 1, if the initial input value is a positive integer and the final output result is 556, the initial input _ _ _ _ _ value may be as follows.
1。
Fill in the blanks (this question 10 small questions, 3 points for each small question, out of ***30 points.
1 1. The number represented by the point on the number axis equal to the distance between two points representing the total of 7 is _ _ _ _ _ _ _ _ _ _ _ _ _.
12. The complementary angle of an angle is smaller than its complementary angle by 20? , then the size of this angle is _ _ _ _ _ _ _.
13. It is known that the sum of monomial 3 and-is a monomial, so _ _ _+_ _ _ = _ _ _ _;
14. Place a set of triangles as shown in the figure, if? BAE= 135？ 17? And then what? The degree of CAD is _ _ _ _.
15. If it is the solution of the equation, the solution of the equation is _ _ _ _ _ _ _.
16. The coefficient of single item is _ _ _ _ _, and the degree is _ _ _ _.
17. If the sum of three consecutive odd numbers is 69, then these three numbers are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
The altitudes of 18.A, b and c are 20 m,-15m and -5m respectively, so the highest point _ _ _ _ _ _ _ _ _ m higher than the lowest point.
19. As shown in the figure, below is the square for placing matchsticks. Please carefully observe and guess that the * * in the first figure has _ _ _ _ _ _ _ roots (represented by the contained algebraic expression) matchsticks.
20. Given the series _ _ _ _ _ _ _ _, let the first number be a 1 and the second number be a2. , the nth number is an, if a? N is the solution of the equation, then n = _ _ _ _ _ _ _ _
Three. Answer the following questions: (***60 points)
2 1.(8 points) Calculation: (1)(- 1)3-? [2-(-3) ] .
22 (8 points) Known and evaluated:
23.( 10) Solve the equation:
( 1) ; (2) ? .
24. (8 points in this question) As shown in the figure, it is known that the line segment AB and CD = AB = the common part BD of CD, and the distance between the line segment AB and the midpoint E and F of CD is 10cm. Find the length of AB and CD.
25. (7 points in this question) The equation about X and its solution are opposite.
(1) Find the value of m;
(2) Find the solutions of these two equations.
26. (8 points for this question) See the picture, you know? BOC=2？ AOC, OD split equally? AOB and AOC=40? , beg? The degree of COD.
27. (The full score of this short question is 1 1)
A middle school bought 30 pens and 45 brushes in recognition of outstanding students in the calligraphy competition, which cost 1755 yuan, and each brush was more expensive than a pen by 4 yuan.
(1) What is the unit price of pens and brushes?
(2)① The school still needs to buy the above two kinds of pens *** 105 (the unit price of each pen remains unchanged). After Mr. Chen finished the budget, he said to Mr. Wang in the finance department. It costs 2447 yuan to buy these two pens this time. Teacher Wang calculated and said, if you only use this money to buy these two pens, then this account must be miscalculated. Please use the equation knowledge you have learned to explain why it is wrong for Mr. Wang to say that he only bought these two pens with this money.
(2) It suddenly occurred to Mr. Chen that the budget also included the signature pen that the headmaster asked him to buy. If the unit price of the pen is an integer less than 10 yuan, please directly write out that the unit price of the pen may be _ _ _ _ yuan through calculation.
I recommend it carefully.