Q (3m? -2m)-2(m？ -3/2m)+ 1。

2) A=2y is known? +2ky-2y- 1，B=-y？ +ky- 1, and the value of 3A+6B has nothing to do with y, so find the value of k.

3) If the fourth power of 3 a, the n+2 power of b, and the m- 1 of 5a multiplied by the 2n+3 power of b are similar terms, find the value of (m+n)(m-n).

4) A factory has 360 kg of raw materials and 290kg of raw materials, and plans to produce 50 pieces of A and B products with these two raw materials. It is known that the production of 1 piece A requires 9 kg of raw material A and 3 kg of raw material B, which can make a profit in 700 yuan. The production of 1 piece B requires 4 kg of raw material A and 10 kg of raw material B. Please design. Which of the several schemes you designed is the most profitable? What is the maximum profit?

5) During the anniversary promotion of a shopping mall, the reward method of "every 100 yuan is sent to 20 yuan in series" is adopted, that is, customers pay 100 yuan per sentence (100 yuan can be cash, bonus coupons or both) and give away 20 yuan bonus coupons; When 200 yuan is full, he will send 40 yuan prize vouchers and push them in turn. One day, a customer spends 15000 yuan at a time, so how much can he buy?

6. The school bought 10 boxes of chalk. 250 boxes were used, and there are 550 boxes left. How many boxes per box?

There are 200 students in the fourth grade. During extracurricular activities, 80 girls went to jump rope. The boys are divided into five groups to play football. How many people are in each group?

8. The canteen brought 150 kg of rice, which was 30 kg less than the flour. How many kilograms of flour does the canteen send?

9. There are 52 peach trees and 6 rows of pear trees in the orchard. There are 20 more pear trees than peach trees. How many pear trees are there in each row on average?

10, the area of a triangle is 840 square meters, the base is 140 meters, and the height is how many meters?

1 1, Li Shifu bought 72 meters of cloth to make 20 clothes for adults and 16 clothes for children. Adult dresses are 2.4 meters each, and how many meters are children's dresses?

12, three years ago, my mother was six times older than my daughter. This year, my mother is 33 years old. How old is my daughter?

13. How long will it take for a car with a speed of 50 kilometers per hour to catch up with a car with a speed of 40 kilometers per hour that left two hours ago?

14. Xiaodong bought 3 Jin of apples and 2 Jin of pears at the fruit shop and paid 15 yuan. 1kg apples are more expensive than 1kg pears in 0.5 yuan. How much are apples and pears per kilogram?

15, A and B start from A and B at the same time, respectively, in opposite directions. A travels at a speed of 50 kilometers per hour, and B travels at a speed of 40 kilometers per hour. A reaches the midpoint 1 hour earlier than B. How many hours does it take for A to reach the midpoint?

16, Party A and Party B set out from A and B at the same time, face to face, and meet two hours later. If A starts from place A and B goes in the same direction at the same time, then A will catch up with B after 4 hours. Given that the speed of A is 15km/, find the speed of B. ..

17. Two ropes with the same length, the first one was cut15m, and the second one was 3m more than the first one. How long are these two ropes?

18. A school bought 7 basketballs and 10 soccer balls and paid 248 yuan. As we all know, the price of each basketball is equivalent to the price of three footballs. How much is basketball and football each?

19) Compare the following dimensions: |-2 |+| 3 | _ _ _ _ |-2+3 |;

|— |+|— | ________ |— |; |0|+|—5| __________ |0—5|; ……

(2) By comparing (1), please analyze and summarize the relationship between |a|+|b| and |a+b| when both a and b are rational numbers.

(3) According to your conclusion in (2), find the value range of x when | x |+5 = | x-5 |.

20. Party A and Party B walk in opposite directions from A and B, with a distance of 50km, namely 1km/h and 1.5km/h respectively. The dog with a leash ran to B at a speed of 3km/h from the beginning, ran back after meeting B, ran to B after meeting A, and so on. How many kilometers did the dog run when A and B met?

2 1. To transport 29.5 tons of coal, transport it three times by trucks with a load of 4 tons, and transport the rest by trucks with a load of 2.5 tons. How many times will it take to complete?

22. The trapezoidal site covers an area of 90 square meters, with an upper floor of 7 meters and a lower floor of 1 1 meter. How high is it?

Its height is x meters.

23. A workshop plans to produce 5,480 parts in April. It has been in production for 9 days, and 908 more are about to complete the production plan. How many pieces will be produced on average every day in these 9 days?

24. Two cars, Party A and Party B, walked in opposite directions from two places 272 kilometers apart at the same time. After three hours, the two cars are still separated by 17km. A travels 45 kilometers per hour, and B travels how many kilometers per hour?

25. There are two classes in grade six in a school, with an average score of 85 in mathematics last semester. There are 40 students in six classes (1) with an average score of 87. 1. There are 42 students in Class Six (2). What is the average score?

26. The school bought 10 boxes of chalk. 250 boxes were used, and there are 550 boxes left. How many boxes per box on average?

There are 200 students in the fourth grade. During extracurricular activities, 80 girls went to jump rope. The boys are divided into five groups to play football. How many people are in each group?

28. The canteen brought 150 kg of rice, which was 30 kg less than the flour. How many kilograms of flour does the canteen send?

29. There are 52 peach trees and 6 rows of pear trees in the orchard. There are 20 more pear trees than peach trees. How many pear trees are there in each row on average?

30. The area of a triangular land is 840 square meters, the bottom is 140 meters, and the height is how many meters?

3 1, Li Shifu bought 72 meters of cloth, just to make 20 clothes for adults and 16 clothes for children. Adult dresses are 2.4 meters each, and how many meters are children's dresses?

32 or 3 years ago, my mother was six times older than my daughter. This year, my mother is 33 years old. How old is my daughter?

33. How long will it take for a car with a speed of 50 kilometers per hour to catch up with a car with a speed of 40 kilometers per hour that left two hours ago?

34. Xiaodong went to the fruit shop and bought 3 Jin of apples and 2 Jin of pears * * * paid 15 yuan. 1kg apples are more expensive than 1kg pears in 0.5 yuan. How much are apples and pears per kilogram?

35. Two cars, A and B, leave from A and B at the same time and go in opposite directions. A travels at a speed of 50 kilometers per hour, and B travels at a speed of 40 kilometers per hour. A reaches the midpoint 1 hour earlier than B. How many hours does it take for A to reach the midpoint?

36. Party A and Party B set out from A and B at the same time and met face to face for 2 hours. If A starts from place A and B goes in the same direction at the same time, then A will catch up with B after 4 hours. Given that the speed of A is 15km/, find the speed of B. ..

37. Two ropes with the same length, the first one was cut15m, and the second one was 3m more than the remaining three times of the first one. How long are these two ropes?

38. A school bought seven basketballs and 10 soccer balls and paid 248 yuan. As we all know, the price of each basketball is equivalent to the price of three footballs. How much is basketball and football each?

39. A lamp in Xiao Ming's house is broken, and now I want to choose one of two kinds of lamps. One is an energy-saving lamp of 1 1 kW (that is, 0.01kw), and the price is 60 yuan; The other is a 60-watt (0.06 kW) white lamp, 3 yuan. These two lamps have the same lighting effect and the same service life. Energy-saving lamps are expensive, but they save electricity; Although white light is cheap, it consumes a lot of electricity. If the electricity bill is 1 yuan/(kwh), that is, 1 kwh and 1 yuan, try to give Xiaoming some suggestions according to what he has learned in the third chapter of the textbook. What can be used to choose which kind of lamp is reasonable?

References:

(1) 1 kw = 1000 watt

(2) Total electricity charge (RMB) = electricity charge per kWh (RMB/kWh) × bulb power (kW )× service time (hours)

(3) 1 kwh = 1 kilowatt continuous use 1 hour

40. In order to save energy, a unit charges electricity according to the following regulations every month: the electricity consumption does not exceed 140 kwh, and it is charged at 0.43 yuan per kwh; If it exceeds 140 degrees, the excess will be charged at 0.57 yuan per degree. If the average electricity bill charged by Mexican consumers in April is 0.5 yuan per kWh, how much should consumers pay in April?

4 1. The ratio of delivery staff to sales staff in the home appliance department of a shopping mall is 1: 8. Due to the obvious increase in the purchase of home appliances this summer, the manager of the home appliance department transferred 22 people from the sales staff to deliver the goods. Results The ratio of delivery staff to sales staff was 2: 5. How many delivery staff and sales staff are there in the home appliance department of this shopping mall?

We are now promoting a certain commodity and reducing the price by 10%. In order to keep the sales amount unchanged, how many percent will the sales volume increase over the original price?

43. The sum of the original unit prices of commodities A and B is 100 yuan. Due to market changes, a commodity has decreased by 10%. B After the price adjustment of the commodity is 5%, the sum of the unit prices of the two commodities has increased by 2%. What are the original unit prices of A and B respectively?

44. The number of people in Workshop A is 30 less than 4/5 of Workshop B. If 10 people are transferred from Workshop B to Workshop A, then the number of people in Workshop A is 3/4 of Workshop B. Find the original number of people in each workshop.

45.A rides a bike from place A to place B, and B rides a bike from place B to place A, both of which advance at the same speed, thus knowing that they will start at 8 o'clock in the morning at the same time. At 10 in the morning, the distance between them was still 36 kilometers, and at 12 at noon, the distance between them was 36 kilometers. How can we find the distance between a and b? (Equation)

46. The length of cars A and B is180m. If two trains travel relatively, it takes *** 12 seconds from the meeting of the front to the departure of the rear; If driving in the same direction, it takes 60 seconds from the front of car A to the rear of car B, and the speed remains unchanged. Find the speed of a car and b car.

47. Two candles with the same length, the thick one burns for 3 hours and the thin one burns for 8/3 hours. When the power goes out, two candles are lit at the same time, and when the phone calls in, they are blown out at the same time. Thick is twice as long as thin, and you can find the time of power failure.

48. At present, there is 400g of salt water, with a salt content of 15%. Teacher Zhang asked the concentration of salt water to be 12%. A classmate added 1 10g water after calculation. Please verify whether the amount of water added by your classmates is correct by solving the equation.

Suppose x grams of water is needed, then: (400+x) *12% = 400 *15% gives x= 100.

In the pasture, the grass grows evenly every day. If it eats 36 sheep, it will eat grass in 8 days. If it eats 30 sheep, it will eat grass in 10 days. If it eats 6 cows, how many days can it eat grass? (It is known that three sheep eat 1 day of grass just like 1 head cow eats 1 day of grass. )

It is known that three sheep ate 1 day of pasture, which is exactly 1 day for cattle, so we can use conditions instead: 36 sheep ate pasture for 8 days, replaced by 12 cows, and ate pasture for 8 days, because the known conditions tell three sheep that 1 day ate pasture is exactly 6544. So we divide 36 by 3 and get 12. The problem is six cows, which is related to the result we just calculated, so we divide the condition by two at the same time to get six cows and eat the pasture in four days.

Xiao Li goes to school from home. When he walked at a speed of 75M/ min for 3 minutes, he found that walking at this speed would be 2 minutes late, so he changed the speed to 90M/ min and arrived 4 minutes earlier. When does he leave home before class?

Xiao Li goes to school from home. When he walked at a speed of 75M/ min for 3 minutes, he found that walking at this speed would be 2 minutes late, so he changed the speed to 90M/ min and arrived 4 minutes earlier. When does he leave home before class?

49. A local train leaves from Station A at a speed of 48 kilometers per hour. 45 minutes later, an express train departs from Station A at a speed of 60 kilometers per hour, taking the same route as the local train. How many hours can the express catch up with the local train?

A local train leaves from Station A at a speed of 48 kilometers per hour. 45 minutes later, an express train departs from Station A at a speed of 60 kilometers per hour, taking the same route as the local train. How many hours can the express catch up with the local train?

50. For a two-digit number, the number of the tenth digit is twice that of the first digit. If the number in the tenth place is reversed from the number in the second place, the number obtained is 36 less than the original number, and the original two digits are found.

For a two-digit number, the tenth digit is twice as large as the second digit. If the number in the tenth place is reversed from the number in the second place, the number obtained is 36 less than the original number, and the original two digits are found.

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