1. Among the following equations, the equation whose solution is -2 is (c).

a、3x—2=2x B、4x— 1=2x+3 C、3x+ 1=2x— 1 D、2x—3=3x+2

2. In the following variants, the shift term is correct (c)

A, x= 12+5 B from 5+x= 12 and 5x-4x = 8 from 5x+8=4x.

C, 10x+2x=4+2 D from 10x-2 = 4-2x, 2x = 3x-5 = 3x-2x = 5.

3. If x=0 is the root of the equation 3x-2m = 4 about x, then the value of m is (b).

a、2 B、—2 C、 1 D、— 1

4. Equation deformation is correct ()

A, B,

C, D,

5. Convert to, the error is ()

A, numerator and denominator cannot be amplified by 10 times at the same time. B, it violates the essence of equality.

C, move the item without changing the symbol d, and there is a symbol error in brackets.

6. The sum of ten digits and one digit of two digits is 7. After adding 45 to this two-digit number, the result is exactly a two-digit number formed after the digits are reversed, so this two-digit number is (a).

a、 16 B、25 C、34 D、6 1

7.A is older than B 15 years old. Five years ago, A was twice as big as B, and now B is (c).

A, 10 years old b, 15 years old c, 20 years old d, 30 years old.

8. Xiaoming bought 80 stamps with 2 yuan *** 16, and spent 80 cents on 18 yuan. If he buys 80 stamps X, the equation can be listed as (c).

a、80x+2( 16—x)= 188 B、80x+2( 16—x)= 18.8

c、0.8x+2( 16—x)= 18.8 D、8x+2( 16—x)= 188

9. On a farm, the sum of the number of hens and pigs is 70, and the sum of the number of legs is 196, so hens are (A) A, 14 B, 16 C, 22 D, 42 more than pigs.

10. Xiaoming deposited 400 yuan money in the bank, with an annual interest rate of 1.8%. Xiao Ming got the interest 36 yuan when it was due, and she saved (B) A, 6 years B, 5 years C, 4 years D and 3 years.

Step 2 fill in the blanks

1. Given that equation 3x2n+3+5=0 is a linear equation, then n = _ _ _ _ _ _ _ _

2. If, then X+Y = _ _ _ _ _ _ _ _ _

3. The sum of five adjacent numbers in a vertical column in a month's calendar is 80, and these five numbers are _ _ 2, 9, 16, 23, 30 _ _.

4. A calendar has four dates in a column, and the sum of the second date and the fourth date is 36, so the third date is _ _ _ 18 _ _.

This summer vacation, Miss Li's family of three went out for a week, and the sum of the dates of this week was 9 1, so Miss Li went home on __ 17__ (Note: 17 is the last day of the trip, is it this day or the next day? )

If the 5th of this month is Wednesday, then the 20th is Thursday.

7. Given that the sum of the two angles is 1800 and the ratio of the two angles is 3: 2, the difference between the two angles is _36 degrees _ (Note: 1800 degrees or 180 degrees? )

8. A wire is 40cm long. If it is enclosed in a quadrilateral, the maximum area is _ _100 _ _ _ _ cm2 (square).

Three. solve problems

1. A math test paper has 20 multiple-choice questions, and it is stipulated that you get 5 points for doing one question correctly, and 1 point for not doing or doing a wrong question. As a result, a student got 76 points. How many questions did he get right?

Suppose we did problem X correctly, and did 20-X. 5x-(20-x)=76 wrong, and x= 16 wrong.

2. Twenty-three students from Grade One (1) in a middle school visited the park on Sunday. The ticket window in the park indicates the fare: 10 yuan/person, and there is a 20% discount for group tickets with more than 25 people (including 25 people). Please design a better ticket purchase scheme for these 23 students.

(1) You need 200 yuan to buy a group ticket for 25 people, that is, 23* 10=230 30 yuan.

(2) Find two individual travelers and buy a group ticket for 25 people, 200 yuan. Two individual customers 16 yuan, first class (1) customers 184 yuan.

3. A bookstore launched a discount card in the promotion. 20 yuan, you can get a 20% discount on books with this card. Once, Li Ming went to the bookstore to buy books. When checking out, he first bought a discount card and then paid with it, saving 12 yuan. So what is the total value of the books that Li Ming bought this time?

0.8x+20=x- 12, x= 160 yuan.

4. Forge a cylinder with a bottom radius of 5cm and a height of 40cm into a cylinder with a bottom radius of 8cm. What is the height? How much has the surface area been reduced?

The volume is unchanged. 3. 14 * 5 * 5 * 40 = 3. 14 * 8 * 8 * h，h= 15.625cm。

Original surface area: 3.14 * 5 * 5 * 2+2 * 3.14 * 5 * 40 = 450 * 3.14.

Late surface area: 3.14 * 8 * 8 * 2+2 * 3.14 * 8 *15.625 = 378 * 3.14.

Therefore, the surface area is reduced by 72*3. 14 cm2, which is 226.08 cm2.

5. A store has a backlog of 65,438+000 items. In order to get rid of these goods as soon as possible, the store adopted the following sales plan, raising the price to 2.5 times the original price and then reducing the price by three times:

Reduce the price by 30% for the first time, 30% for the second time and 30% for the third time. The sales results of three price reductions are as follows:

Number of price reductions one, two, three

The number of pieces sold is 10 40.

Q: (1) What is the percentage of the original price after the third price reduction?

(2) The goods are sold according to the new sales plan, which plan is more profitable than the original price?

(1)34.3%*2.5=85.75. Obviously, compared with the original price, the price reduction is not much.

(2) Obviously, the new sales plan is more profitable. Calculate and set the original price A. The original price and total sales price are 100A.

New sales plan:

2.5A * 0.7 * 10+2.5A * 0.7 * 0.7 * 40+2.5A * 0.7 * 0.7 * 0.7 * 50 = 109.375 a .