How to make linear equation with one variable? Use an example to analyze,

How to make linear equation with one variable? Use an example to analyze,

[summary of knowledge and methods] 1. Two steps of solving practical problems by using equations. (1) steps of solving practical problems by using equations: (1) make clear the meaning of the problem, find out the unknown number and express it with X; (2) find out the equal relationship between quantities in the practical problems, make equations; (3) solve the equations; (4) check and write the answers. (2) the key of solving practical problems by using equations. (2) after making clear the meaning of the problem, find out the equal relationship between quantities in the practical problems, Set up the unknowns properly, and list the equations. (3) use the general number related series equations to solve the application problems. First, the unknowns must be clear, and it will not be difficult in the future. According to the conditions, set up the equations with the unknowns set by yourself. Some problems need to use the unknowns several times, which is an empirical problem. Come on! I believe you can learn it well! These methods only play a transitional role, It's not necessary to really learn equation well. Add a point: when you look at the questions, you first look at the questions, and then carefully look at the conditions, see which are known and which are unknown. Then think about the conditions required to ask for the answers, and then use the known conditions to obtain those conditions (some simple questions will directly give those conditions), Finally, find out the answer. Solving application problems with linear equation of one variable is only to change the answer or the condition needed to find the answer to x, so as to better analyze the problem. If you are good at mathematics, in fact, linear equation of one variable is not too difficult
The following is the general form of linear equation with one variable
According to the meaning of the title, we can get the following conclusion: (general terms, many words can be omitted to explain, which are deeply loved by the majority of middle school teachers and students)
Formula (that is to say, you should substitute x into the formula, just like you check the arithmetic, and take x as the answer to find the known condition)
Solving the equation
Answer: The application problem of or one variable linear equation is the key and difficult point in the first semester of grade seven. Its learning is of decisive significance for solving inequality application problems and function problems in the future. If you don't learn it well, it will be more difficult to learn in the future. Generally, the first step in solving problems is to set up unknowns. There are several ways to deal with unknowns: 1, If a is 8 more than B, we usually set the smaller one as X, which is not easy to make mistakes in calculation; 2. If there is a multiple relationship, if the number of the math group is 5 times that of the English group, we set one time quantity as X, and use multiplication to express the rest quantity, which is convenient for calculation; 3. In the fraction application problem, we set the unit '1' as X, 4, in the comparison problem, we set one number as X, 5, in the sum problem, Let's set any one of them as X. for example, there are 50 students in two classes
The basic steps of solving practical problems are as follows
1. According to the requirements of the topic, set up the appropriate unknowns;
2. Find out the equivalent relationship according to the actual situation of the topic, and express it with the literal relation;
3. According to the equivalent relation, each term in the relation is expressed by numbers or unknowns, and the equation is listed;
4. Solve the equation and calculate according to the problem;
5. Replace the solution of the equation with the test of the original problem. The difficulty is to find out the equivalent relationship in the second step. The relationship in some problems is obvious, while others are implicit. We need to experience it carefully
Let me give you two examples:
1: Grandfather and grandson play chess. Grandfather wins one game and grandson wins one game and gets one point. Grandson wins one game and gets three points. After they play 12 games (no draw), they get the same score. How many games have they won?
Analysis: it belongs to the problem of sum, so let any one be X. if grandfather wins x, Sun Tzu wins (12-x) sets. The equivalent relation in the title is that grandfather score = Sun Tzu score, grandfather score is expressed by X, Sun Tzu score is expressed by 3 (12-x), so the equation of this problem is x = 3 (12-x). If the solution is x = 9, then 12-x = 12-9 = 3, so grandfather wins 9 sets, Sun Tzu wins 3 sets
2: A conical container with a bottom diameter of 30 cm and a height of 8 cm is filled with water, and then the water is poured into an empty cylindrical container with a bottom diameter of 10 cm. How high is the water in the cylindrical container?
Analysis: there is no obvious type of this problem, so we directly set the problem, let the water in the cylindrical container have x cm, the equivalence relation in the problem is implied, that is, the volume of water in the conical container = the volume of water in the cylindrical container, respectively expressed by the following equation 1 / 3 * 3.14 * (30 / 2) (30 / 2) * 8 = 3.14 (10 / 2) (10 / 2) x, and the solution is x = 24

How to make a linear equation of one variable
How to analyze the quantity relation in the problem? How to ask the unknown number and the known number in the problem? How to use letters to express the unknown number in the problem? How to find the equality relation in the problem and list the equation

The skill of making linear equation of one variable:
[summary of knowledge and methods] 1. Two steps of solving practical problems by using equations. (1) steps of solving practical problems by using equations: (1) make clear the meaning of the problem, find out the unknown number and express it with X; (2) find out the equal relationship between quantities in the practical problems, make equations; (3) solve the equations; (4) check and write the answers. (2) the key of solving practical problems by using equations. (2) after making clear the meaning of the problem, find out the equal relationship between quantities in the practical problems, Set up the unknowns properly and list the equations. (3) use the general series of equations of quantity relation to solve practical problems. First of all, the unknowns must be clear
If you are good at mathematics, in fact, the equation is not too difficult. The following is the general format of the equation: (copy the question, just change "what" to X or set according to the meaning of the question), We can omit a lot of words to explain it, which is very popular among teachers and students in middle schools: to solve the equation (that is, you need to substitute x into the equation, just like you check the arithmetic, and take x as the answer to find the known condition) is to solve the equation (that is, you need to solve the equation)
Generally, the first step in solving a problem is to set up the unknowns. There are several ways to solve the unknowns: 1. When there is a comparative relationship, for example, a is 8 more than B, we usually set the smaller one as X, so that the calculation is mainly based on addition, which is not easy to make mistakes; 2. When there is a multiple relationship, for example, the number of the math group is 5 times that of the English group, we set one time quantity as X, and use multiplication to express the rest quantity, which is convenient for calculation; 3, In the practical problems of scores, we set the unit '1' as X, 4. In the problems of comparison, we set a number as X, 5. In the problems of sum, we can set any one as X. for example, there are 50 students in two classes. The basic steps to solve the practical problems are: 1. To find out the appropriate unknown number according to the problem; 2. To find out the equivalent relationship according to the actual situation of the problem and express it with the literal relationship; 3, According to the equivalence relation, express each item in the relation with numbers or unknowns, and list the equation; 4, solve the equation, and calculate according to the problem; 5, substitute the solution of the equation into the original problem test. The difficulty is the second step, to find out the equivalence relation. Some problems are obvious, while others are implicit, which need us to experience carefully, Let me give you two examples: 1: when grandfather and grandson play chess, grandfather wins one game and grandson wins one game and scores one point, while grandson wins one game and scores three points. After they play 12 games (no draw), how many games have they won? Analysis: it belongs to the problem of sum, so set any one as X. if grandfather wins x, grandson wins (12-x). The equivalent relationship in the question is that grandfather scores = grandson scores, Grandfather's score is expressed by X, and grandson's score is expressed by 3 (12-x), so the equation of this problem is x = 3 (12-x). If the solution is x = 9, then 12-x = 12-9 = 3, so grandfather wins 9 sets and grandson wins 3 sets. 2: fill a conical container with a bottom diameter of 30cm and a height of 8cm, and then pour the water into an empty cylindrical container with a bottom diameter of 10cm, How high is the water in the cylindrical container? Analysis: there is no obvious type in this problem, so we directly set the problem, let the water in the cylindrical container have x cm, the equivalency relationship in the problem is implied, is the volume of water in the conical container = the volume of water in the cylindrical container, respectively expressed by the following equation 1 / 3 * 3.14 * (30 / 2) (30 / 2) * 8 = 3.14 (10 / 2) (10 / 2) x, the solution is x = 24

(online) function f (x) = 2x ^ 3 + 6x ^ 2 + 7 (1) find the maximum value of monotone interval (2) in interval [- 2,5]
ditto

If f '(x) = 6x & sup2; + 12x = 6x (x + 2), then f (x) increases on (- ∞, - 2), decreases on (- 2,0), and increases on (0, + ∞). The minimum is f (0), and the maximum is f (- 2) and f (5)

80*（X+5）=180X
For example, moving items, merging similar items, transforming coefficients into one or something,

80×（x＋5）＝180x
Remove bracket: 80x + 400 = 180X
Transfer: 80x-180x = - 400
Merge similar items: - 100x = - 400
Divide both sides by (- 100) and change the coefficient of X to 1,
x＝（－400）÷（－100）
x＝4

First simplify, then evaluate: M / M + 3-6 / M-9 △ 2 / M-3, where M = - 2

Is it m / M + 3-6 / M - 9 / 2 / M - 3 or M / M + 3-6 / M - 9 / 2 / M-3

Does the square include the acceleration in the formula that uses the successive difference method to calculate the acceleration?
Is it △ x = at & # 178;, or △ x = (at) &# 178;?

It does not include acceleration. It is △ x = at & # 178!

Solve the equation! Fast! 11 / 2 △ 0.4 = 1.35 △ X; 12 + 3 (x-1) = 18; 5x + 1 = 3 + 3 (1-x); X △ 48 = 24 △ 32;

11/2÷ 0.4=1.35÷ x；
11/2x=1.35×0.4
5.5x=0.54
x=27/275
12+3（x-1）=18；
12+3x-3=18
3x=9
x=3
5x+1=3+3（1-x）；
5x+1=3+3-3x
8x=5
x=5/8
x÷ 48=24÷ 32；
32x=24×48
2x=24×3
x=36

Find all angles X between 0 ° and 360 ° satisfying 3cos x = 8 Tan X

3cosx = 8sinx/cosx
3cos^2 - 8sinx = 0
3 (1-sin^2) - 8sin=0
3sin^2 + 8sin - 3 = 0
(3sin-1)(sin+3) = 0
sinx = 1/3
x = arcsin(1/3)
There are two (1,2 quadrants) ~ 19.5 and 160.5

(32-x) (20-x) = 540 cross multiplication

640-52x+x^2=540
x^2-52x+100=0
(x-50)(x-2)=0
x=50,x=2

(3, - 5) the position coordinates of 2 unit lengths of downward translation are, and the position coordinates of 3 unit lengths of right translation are

(3, - 5) the position coordinates of (3, - 7) are obtained by moving down two unit lengths,
The coordinates of the unit length of 3 are (6, - 7)
Study happily