When what is the value of X, the value of equation (5x + 1) / 2-3x is 5 times larger than that of equation (7x-5) / 3?

When what is the value of X, the value of equation (5x + 1) / 2-3x is 5 times larger than that of equation (7x-5) / 3?

Let Y1 = (5x + 1) / 2-3x, and simplify Y1 = (1-x) / 2, which is a decreasing function
Let y2 = (7x-5) / 3 be an increasing function
So y1-y2 = 5
The solution is x = - 1
So when x is greater than - 1, the problem holds

When what is the value of X, is the value of formula 5x + 1 / 2-3x equal to that of formula 7x-7 / 3?

5x+1/2-3x=7x-7/3
15x+3-18x=14x-14
-3x-14x=-14-3
-17x=-17
∴x=1

How to divide the m-th power of 8 by the m-th power of 2 times the m-th power of half

The m-th power of 4 is obtained by dividing the m-th power of 8 by the m-th power of 2. Then the m-th power of 4 is multiplied by half of the m-th power to get the m-th power of (4 times half), that is, the m-th power of 2

The distance between car a and car B is 150 meters. The speed of car a is 90 km / h, and the speed of car B is 70 km / h. car a and car B go in the same direction at the same time. After a few hours, car a catches up with car B? (train equation solution)

Let car a catch up with car B after X hours
90X-70X=150
20X=150
X = 7.5 hours

There is a column of numbers, which are arranged into 1, - 2,4, - 8,16, - 32 according to certain rules. What is the nth number? (n is a positive integer,
(expressed by a formula containing n)
Take out the sum of three adjacent numbers in this column, which is 3300, and find out what are the three numbers?

(-2)^(n-1)
The N-1 power of negative two

The sum of all integers whose absolute value is less than 2008 is______ ．

All integers with absolute values less than 2008 are - 2007, - 2006, - 2005 The sum is - 2007 + (- 2006) + (- 2005) + +2005 + 2006 + 2007 = 0

What are the teaching requirements of the sixth grade mathematics volume I of Beijing Normal University Edition

（1） Number and algebra
1. Unit 2 "Application of percentage". In this unit, students will understand the meaning of "increase percentage" or "decrease percentage" in specific situations, deepen their understanding of the meaning of percentage, and be able to use the relevant knowledge of percentage or equations to solve some practical problems, so as to improve their ability to solve practical problems, Feel the close relationship between percentage and daily life
2. Unit 4 "understanding of ratio". In this unit, students will experience the process of abstracting ratio from specific situations, and understand the significance of ratio and its relationship with division and score; in actual situations, students will realize the necessity of simplifying ratio, and will use the properties of constant quotient and the basic properties of score to simplify ratio; they will be able to use the significance of ratio, To solve the practical problems of distribution according to a certain ratio, to further understand the significance of ratio, to improve the ability to solve problems, and to feel the wide application of ratio in life
（2） Space and graphics
1. Unit 1 "circle". In the study of this unit, students will understand the circle and its symmetry through observation, operation and other activities, realize the relationship between radius, diameter, radius and diameter in the same circle, understand the essential characteristics of the circle and the role of the center and radius of the circle, and be able to draw a circle with compasses; in combination with specific situations, through hands-on experiments, pendulum operation and other practical activities, Explore and master the calculation method of circumference and area of circle, experience the idea of "turning curve into straight"; combine the process of appreciating and drawing patterns, experience the application of circle in pattern design, be able to design simple patterns with compasses, feel the beauty of patterns, and develop imagination and creativity; develop the concept of space through observation, operation, imagination, pattern design and other activities; combine with specific situations, develop the concept of space, Experience mathematics is closely related to daily life, can use the knowledge of circle to explain simple phenomena in life, solve some simple practical problems; combined with the reading of the development history of PI, experience the process of human continuous exploration of mathematical knowledge, feel the charm of mathematical culture, stimulate national pride, and form a positive emotion for mathematics
2. Unit 3 "transformation of graphics". In this unit, students will experience the process of making complex graphics through translation or rotation of a simple graphics through observation, operation and imagination, and can express the transformation process of translation or rotation of graphics in an orderly way, develop the concept of space, and experience the process of using translation, rotation or axisymmetric graphics for pattern design, It can flexibly use translation, rotation and axial symmetry to design patterns on checkerboard paper, and experience the magic of the graphic world by appreciating and designing beautiful patterns
3. Unit 6 "observing objects". In this unit, students will be able to correctly identify the shape of the three-dimensional figure (5 small cube combinations) observed from different directions (front, side and top), and draw sketches; they will be able to restore the three-dimensional figure (5 cube combinations) according to the plane figure observed from front, side and top, Further experience: the shape of a three-dimensional figure can be determined by observing from three directions; the number range of cubes needed to build the three-dimensional figure can be determined according to the shape of a plane figure observed from two given directions; the process of abstracting the eyes, line of sight and observation scope into points, lines and regions respectively, Feeling observation range changes with the change of observation point and angle, and can use the knowledge to explain some phenomena in life
（3） Statistics and probability
Unit 7 "Statistics". In this unit, students will learn about compound bar chart and compound broken line chart through bowling games, precipitation of two cities and other examples, and feel the characteristics of compound bar chart and broken line chart; they can choose compound bar chart and compound broken line chart according to their needs to effectively display data; they can read simple compound statistical chart, Make simple judgments and predictions according to the statistical results, and communicate with peers
（4） Comprehensive application
This textbook has arranged three major thematic activities, namely "Mathematics and sports" and "numbers in life", aiming at promoting students to comprehensively use the knowledge they have learned to solve practical problems in a certain field of life. The textbook also has arranged a special topic of "looking at pictures to find relationships", aiming at enabling students to realize that pictures can depict relationships intuitively, clearly and simply, In these activities, students will comprehensively use the knowledge and methods they have learned to solve practical problems, feel the role of mathematics in daily life, obtain some preliminary experience and methods of mathematical activities, develop the ability to solve problems and think with mathematics, and feel the interrelationship between mathematical knowledge, Experience the function of mathematics; develop interest and confidence in mathematics learning in the process of cooperation and communication with peers
（5） Organize and review
There are two arrangement and review in the textbook. The arrangement and review change the mode of simple problem-solving and pay attention to the development of students' consciousness of self reflection. Each arrangement and review is divided into three parts: the arrangement of the learned content, putting forward mathematical problems and trying to solve some exercises
The column "what have you learned" aims to encourage students to review and reflect on what they have learned. They can use lists or other forms to sort out the main contents
"Use the knowledge to put forward related mathematical problems, and try to solve problems", the purpose is to cultivate students' ability to put forward and solve problems; deepen the understanding of the knowledge in the process of solving problems; review their own experience and progress in the process of learning

There are three kinds of balls in the box. The ratio of the number of yellow balls to the number of red balls is 2:3, and the ratio of the number of red balls to the number of white balls is 4:5?

Yellow: Red: white = 8:12:15
175÷（8+12+15）=5
Red ball = 12 × 5 = 60
Your praise is my motivation
I drink Coca Cola in the desert, sing karaoke, ride a lion, drive ants, and answer questions for you with a keyboard in my hand!

How many centimeters are 60 inches and 80 inches?

1 inch = 0.0254m = 2.54cm
60 in = 152 cm
80 in = 203.2 cm

1. 80% of a number is 16, and 15% of the number is ()
2. The ratio of the number of goats to the number of sheep is 8:5, and the number of sheep is less than that of goats ()
3. To build a canal, 60% of it has been built, 840 meters has been built, and () meters has not been built
4. The number of boys is 4 / 5 of the number of girls, girls account for ()% of the class, boys account for ()% of the class
5. The number a is 20, the number B is 60% of the number a, the third quarter of the number C is the number B, and the average of the three numbers is ()
Let's talk about the practice of this kind of problem

1. 80% of a number is 16, and 15% of this number is (3) 2. The ratio of goats to sheep is 8:5, and sheep are less than goats (0.375) 3. Build a canal, 60% of which has been built, 840 meters of which has been built, and (1400) meters of which has not been built 4. The number of boys is 4 / 5 of that of girls, and girls account for (55.5)%