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The general steps of solving practical problems with equations Be brief (no more than 27 words)
The steps are basically the same as those for solving practical problems with one variable first-order equation. The general steps for solving practical problems with one variable second-order equation are as follows: (1) review the problem: understand the problem, review the meaning of the problem, make clear which are known quantities, which are unknown quantities, and the relationship between them, Set element is divided into direct set element and indirect set element (3) series equation: according to the equivalence relation given in the title, list the quadratic equation with one variable in line with the meaning of the title (4) solution equation: find the solution of the listed equation (5) test root: test whether the value of the unknown number meets the meaning of the title (6) write the answer
50 points to solve the application problem of the system of linear equations with 2 variables (there must be a process!)
Party A and Party B go to a certain place twice to buy a certain factory product. The unit price of the two purchases is different, a yuan / kg and B yuan / kg respectively. Party A buys 1000 kg each time, while Party B buys 1000 yuan each time. (1) request the average unit price of the two purchases
(2) Please compare who has the lower unit price
(1) Unit price (yuan / kg) quantity (kg) total price (yuan) the first a 1000 AA 1000 / a 1000 the second B 1000 BB 1000 / b 1000 the average unit price of two times a: (1000A + 1000B) / (1000 + 1000) = (a + b) / 2 the average unit price of two times B: (1000 + 1000) / (1000 / A + 1000 / b) = 2Ab / (a + b)
Solving equations and solving application problems,
1. To bring 200 kilometers of water into the city, the task was given to the construction teams a and B, with a construction period of 50 days. After 30 days of cooperation, team B had to leave for 10 days because of other tasks, so team a speeded up and repaired 0.6 kilometers more every day. After 10 days, team B came back. In order to ensure the construction period, team a kept the same speed, and team B was faster than
RELATED INFORMATIONS
- 1. Set up equations to solve practical problems== The ratio of output per unit area of a and B crops is 1:1.5. Now we need to divide a 200 meter long and 100 meter wide rectangular land into two small rectangles. How to divide the two crops into two parts, so that the ratio of total output value of a and B crops is 3:4 (the result is taken as an integer) Tip: if the length is ab, take a little e, AE = XM, be = YM To calculate the process! ~ ~ will add points~~~~
- 2. 1: If the bus starts from a for 9 hours, the distance between the two vehicles is 3000 km. How many meters is the distance between a and B 2: Car a and car B leave from city a and city B at the same time, and they can meet each other in six hours. Now car a starts from city a, and it's 210 kilometers away from city B one hour later. Car B starts from city B, and it's 230 kilometers away from city a one hour later. How many kilometers are there between city a and city B 3: A batch of pesticides was transported to a village. 4 / 7 of the total amount was used in the first day, 12 kg more than twice the amount used in the second day. At this time, the ratio between the amount used and the rest is 27:8. How many kg does this batch of pesticides weigh 4: A truck team transported a batch of cement from the factory to the construction site. On the first day, it transported more than 1 / 4 7 tons of all cement, and on the second day, it transported the remaining 2 / 5 more than 2 tons. At this time, it transported 5 / 18 of all cement. How many tons of original cement 5: After 1 / 3 of the coal in pile a and pile B is transported to pile B, 40% of the coal is transported from pile B to pile A. at this time, there are 48 tons in pile a and 42 tons in pile B. how many tons of coal are there in pile a and pile B
- 3. In the first quarter of 2006, the output value of a hardware factory in a city was 150000, 200000 in the second quarter, 230000 in the third quarter, 280000 in the fourth quarter, 10 in the first quarter, 12 in the second quarter, 15 in the third quarter and 18 in the fourth quarter. According to the average quarterly growth rate in 2006, how many million annual output value in 2007?
- 4. The explanation of intersecting line and parallel line How to answer? From which aspects
- 5. A family of three travel to the North during the holiday. There are two local travel agencies, a and B, whose prices are the same, but there are concessions for family travel. A travel agency says that adults don't discount, while children get 60% off. B travel agency says that all three people get 20% off. After accounting, B travel agency wants 240 yuan cheaper. How much is the adult's price?
- 6. Make a straight line through a vertex of a polygon. After cutting off two corners of the polygon, the sum of its internal angles is 1260 degrees. What is the number of original sides of the polygon?
- 7. As shown in the figure, P is the point on the fixed length line AB, and C and D respectively start from P and B and move to the left along the line AB at the speed of 1cm / s and 2cm / S (C is on the line AP and D is on the line BP) (1) If there is always PD = 2Ac when C and d move to any time, please indicate the position of P on line ab (2) Under the condition of (1), q is a point on the line AB, and aq-bq = PQ (3) Under the condition of (1), if C and d move for 5 seconds, then C stops and D continues to move (D is on line Pb), m and N are the midpoint of CD and PD respectively. The following conclusions are drawn: ① the value of PM + PN remains unchanged; ② the value of PM + PN remains unchanged. Only one of the two conclusions is correct. Please find out the correct conclusion and evaluate it
- 8. Three seventh grade math problems. Anxious~ 1. There are several numbers, denoted as the first power of a, the square of a, the cube of a,..., the nth power of A. It is stipulated that the square of a = the first power of 1 / 1-A, the cube of a = the square of 1 / 1-A, the fourth power of a = the third power of 1 / 1-A.. The nth power of a = the nth power of 1 / 1-A If the power 1 of a = - 1 / 2, what is the value of the power 1000 of a 2. From the third grade of primary school, a classmate has used the lucky money to subsidize hope primary school on the first day of school every year, and every year he always subsidizes m yuan more than the last one. If he subsidizes hope primary school for n yuan in the fifth grade, then he subsidizes hope primary school in the seventh grade this year________ (n > 2m) 3. If a round paperboard is cut into several sectors according to the requirements, the operation is as follows: for the first cutting, the round paperboard is equally divided into four sectors, for the second cutting, one of the four sectors obtained last time is equally divided into four sectors, and then the second cutting is carried out (1) Please write down the total number of sectors of the 1st, 2nd, 3rd, 4th and Nth power (2) According to the above rules, how many sector paperboards can be cut from the original round paperboard after the 2008 operation?
- 9. Hurry! Ten minutes to! Very simple elementary school mathematics sixth grade score application problem! Xiaoyue walked from the East Village to the West Village. After walking 3 / 8 of the whole venue, she walked 60 meters, 20 meters more than the key point. How many meters is the distance between the East and west villages?
- 10. Hurry! Ten minutes to! Primary school mathematics sixth grade score reduction method to solve application problems! The main road team built a road. On the first day, it built 1 / 5 and 100 meters of the total length. On the second day, it built the remaining 2 / 7 and 500 meters. How many meters is the total length of the road? (use equation solution) Write down the process again, please!
- 11. There are several three legged stools and four legged chairs, and they are all manned. If there are 39 legs, how many people are there?
- 12. There are several stools and chairs in the room. Each stool has three legs and each chair has four legs. When they are all sat on, there are 43 legs, including two for each person Leg, how many people are there in the room
- 13. There are three legged chairs and four legged chairs in the classroom. It is known that there are 60 chair legs and 15 chairs, How many are the three legged chair and the four legged chair?
- 14. Use a 2-meter-long wood, saw into four pieces of the same length, used to make stool legs, the height of the stool is about______ Decimeter
- 15. A student desk consists of a desk top and four legs. If one cubic meter of wood can make 50 desks or 300 legs, there are 15 cubic meters of wood A student desk is composed of a desk top and four legs. If one cubic meter of wood can make 50 desks or 300 legs, and there are 15 cubic meters of wood, please design how much wood to use for the desk top and how much wood to use for the legs?
- 16. A student desk consists of one desk top and four legs. If one cubic meter can make 50 desks or 300 legs, there are 15 cubic meters of wood, Please design how much wood to use for the table top and how much wood to use for the table legs
- 17. A student desk consists of a desk top and four legs. If one cubic meter of wood can produce 50 desks or 300 legs, there are 15 cubic meters of wood, Make them match (equation of first degree with one variable)
- 18. If a round table can be made of 5 cubic meters of wood, then the table can be made of 1 cubic meter of wood and 5 legs For example, please list the equation of one dollar
- 19. We need to solve the linear equation with one variable For a three digit number, a hundred digit number is 4 times smaller than a single digit number, and a ten digit number is 1 times larger than the sum of a single digit number and a hundred digit number. The value of the three digit number is just 25 times that of the ten digit number
- 20. When an aircraft flies between the two cities, the wind speed is 24 km / h, it takes 2 hours and 50 minutes to fly against the wind, and it takes 3 hours to fly against the wind to calculate the speed of the aircraft when there is no wind