First, choose carefully (this question has a total of 10 small questions, each with 3 points, out of 30 points. Only one of the four options given in each question below is correct. )
1.=( ).
a . 0 B- 2 c .+2d . 1
2. The following calculation is incorrect ().
a . 2-5 =-3 b .(-2)+(-5)=-7
C.=-9d .(-2)-(- 1)=- 1
The scientific notation of 3.35 1000 is correct ().
a . 0.35 1× 106 b . 3.5 1× 105 c . 3.5 1× 106d . 35. 1× 104
4. The following statement is true ().
A. it is not a monomial. B.0 is not a monomial. The coefficient of C.-is-1D. It is a monomial.
5. In the following formula, () is the same item.
A.4 and 4 BC
6. The correct result in the following calculation is ().
A.4+5ab=9ab
7. "The statement that the temperature is 6℃ lower than -3℃ is correct ().
A.-3+6 = 3 b .-3-6 =-9 c .-3+6 =-9d .-3-6 =-3
8. The solution of the equation is ().
A. the sixth century BC.
9. In the process of solving the following equation, the deformation is correct ().
A. From 2- 1 = 3 to 2 = 3-1b. From.
C.=-d from -75 = 76. 2-= 0 from-= 1。
10. Of the three consecutive odd numbers, the largest is 2n+3, so the smallest is ().
A.B. C. D。
Second, patiently fill in (6 small questions in this question, 3 points for each small question, full score 18 points)
1 1. If it is a polynomial of degree seven, the value of m is _ _ _ _ _ _ _.
12.=____________.
13. The sum of all integers between -3 and 2 (inclusive) on the number axis is equal to.
14. Observe the arrangement of the following numbers and fill in the appropriate numbers in the blanks:-1, 3, -9, 27, 243, …
15. So, algebra and 2 are opposites.
16. If is, the value of is.
Third, answer with your heart (this big question consists of 9 small questions with a score of *** 102, and the answer requires a description of the proof process or calculation steps)
17. Calculation (2 small questions in this question, 6 points for each question, full score 12 points).
( 1)
(2)
18. Simplification (2 small questions in this question, 6 points for each question, full score 12 points)
( 1) (2)
19. Solve the following equation (there are 2 small questions in this question, with 6 points for each question, and the full score is 12 points).
( 1) (2)
20. (The full mark of this question is 8)
Simplify first, then evaluate:, where
2 1. (The full mark of this question is 8)
There is a spring with an original length of 10 cm. After hanging a heavy object (no more than 50 grams), its length will change. Please answer the following questions according to some data in the table below:
Mass (g) 1 234...n
Elongation (cm) 0.5 1. 1.5 2…
Total length (cm)10.5111.512 ...
(1) How many grams of weight should be hung to make the spring extend 5 cm?
(2) When the hanging weight is x grams, the total length of the spring is expressed by algebraic expression.
(3) When x = 30g, find the total length of the spring at this time.
Volume II (50 points)
22. (The full mark of this question is 12)
(1) known value;
(2) the known and discovered value.
23. (The full mark of this question is 12)
According to the charging standard of mobile phone A, for long-distance calls from A to B, the charge is 1.8 yuan for the first 3 minutes, and 0.8 yuan for every minute after 3 minutes.
(1) If the call time is x minutes (x≥3), how much should I charge?
(2) If according to this standard, it took 8.2 yuan for Xiao Wang to make a phone call, how many minutes did Xiao Wang make a phone call?
24. (The full mark of this question is 12)
Xiaohong does a math problem "Two polynomials A, B and B are both, try to find the value of A+B". Xiaohong mistook A+B for A-B, and the answer (correct calculation) is.
(1) Try to find the correct result of A+B;
(2) Find the value of A+B when x=3.
25. (The full mark of this question is 14)
Solving problems with holistic thinking: In order to simplify problems, we often regard a formula as a number (integer).
Try to answer the following questions according to the prompt.
(1) If the value of algebraic expression 2x2+3y is -5, find the value of algebraic expression 6x2+9y+8.
(2) It is known that A+B = 3x2-5x+ 1 and A-C =-2x+3x2-5. When x = 2,