Application of equation Some students of a class take part in the community tree planting activities. If there are 7 seedlings, there are 5 lessons left. If each student plants 8 seedlings, there is 1 person who plants one less. How many people take part in the tree planting activities

Application of equation Some students of a class take part in the community tree planting activities. If there are 7 seedlings, there are 5 lessons left. If each student plants 8 seedlings, there is 1 person who plants one less. How many people take part in the tree planting activities

Six
Set up a tree planting group with X people and Y trees,
7x+5=y,
8x-1=y
x=6
y=47

In order to help the people in Wenchuan earthquake area rebuild their homes, a school in our city called on teachers and students to donate voluntarily. It is known that the first donation totaled 90000 yuan, and the second donation totaled 120000 yuan. The second donation per capita was 1.2 times of the first donation per capita, and the number of donors was 100 more than the first donation. How many yuan were the first and second donations per capita?

Suppose that the first donation per capita is x yuan, then the second donation per capita is 1.2x yuan. According to the meaning of the question: 90000x + 100 = 1200001.2x, the solution is: x = 100. The test shows that x = 100 is the root of the original equation. 1.2x = 120 answer: the first donation per capita is 100 yuan, and the second donation per capita is 120 yuan

Mathematical problems (equation solving application problems)
1. There are 10 dimes, 50 dimes and 1 yuan silver coins each. 15 of them are worth 7 yuan in total. How many dimes do you take for each of them?
2. The whole journey from land a to land B is 3.3km, including one uphill, one level road and one downhill. If the uphill is kept at 3km per hour, the level road is kept at 4km per hour and the downhill is kept at 5km per hour, then it takes 51 minutes to travel from land a to land B and 53.4 minutes to travel from land B to land a?
3. Car a and car B respectively move on the circular track with a circumference of 600 meters at a uniform speed. Car a has a faster speed. When the two cars move in the opposite direction, they meet every 15 seconds. When the two cars move in the same direction, they meet every 1 minute to calculate the speed of the two cars
4. Someone bought the same commodity from both places with different quantities at 210 yuan and 700 yuan respectively, and each commodity in place a used 3.5 yuan more than that in place B. when he sold at 25 yuan per commodity, he earned 340 yuan in total. How many pieces of this commodity did he buy from both places?

1. 0.1 x + 0.5 y + Z = 7 x + y + Z = 15, because x, y, Z are integers and less than or equal to 10, so x = 5; y = 7; Z = 32, set uphill, flat, downhill distance as X, y, ZX + y + Z = 3.3 X / 3 + Y / 4 + Z / 5 = 51 / 60 x / 5 + Y / 4 + Z / 3 = 53.4 / 60 x = 1.2, y = 1.6, z = 0.53, set car a and car B

On the application of equation
Xiaoming went shopping with his mother on Sunday and bought a suit of clothes at a clothing store at a discount of 20%, which saved 15 yuan compared with the marked price?
Factory a has 100 tons of steel stock and uses 45 tons a month; factory B has 82 tons and uses 9 tons a month. After x months, if the two stocks are equal, then x is equal to?
Xiaoming's father bought two carpets. He told Xiaoming that the area of the small carpet was exactly 1 / 3 of the area of the large carpet, and the sum of the two carpets was 20 square meters. Xiaoming soon came to the conclusion that the area of the two carpets was?
A two digit number is four times the number of one digit and ten digit number. If the number of one digit and ten digit number are exchanged, then the heart number of Tao is 54 times larger than the original number. Then what is the original number?
An adult can eat four breads at a meal, and two children can eat one at a meal. There are 7 adults and children, and there are 14 breads. How many breads are there for adults and children?
One of the main players of a basketball team scored 28 points in 14 of 22 shots in a game. Apart from three three-point shots, how many two-point shots and free throws did he hit?

1. Let the original price be x 0.8x = X-15, x = 75
2.100-45x=82-9x x=1/2
3. Let the area of large carpet be X. if there is a question, the area of small carpet is 1 / 3x. X + 1 / 3x = 20, x = 15. The area of large carpet is 15, and that of small carpet is 5
The following you try according to this, do not understand and then ask me to get off work first

There are 5 tons of yellow sand on the construction site. Two fifths of it is used up on the first day, and one fourth of it is used up on the second day. How much is left?

I think it's 1-2 / 5-1 / 4

If the quadratic function y = ax ^ 2 + BX + C is symmetric about the Y axis, then it should satisfy?

Should it be the image about that symmetry?
You are also too careless, did not learn mathematics well, ha ha!
For Y-axis symmetry, the equation x = 0
That is: B = 0
We get b = 0

The number of female workers in a factory accounts for 33% of the total number of workers in the factory, 102 less than that of male workers. How many male workers are there?

102÷（1-33%-33%）×（1-33%）
=102÷34%×67%
=300×67%
=201 people

Factorization (y ^ 2 + 6y) ^ 2 - (6y + 36) ^ 2

(y^2+6y)^2-(6y+36)^2
=(y^2+6y+6y+36)(y^2+6y-6y-36)
=(y+6)^2(y+6)(y-6)
=(y+6)^3(y-6)

There were 48 students in class 6 (1), of which boys accounted for 5 / 8 of the class. Later, several boys were transferred, and now the number of boys accounts for 11 / 20 of the class,
How many boys turn away?

Female = 48 × (1-5 / 8) = 18
Now = 18 (1-11 / 20) = 40
Turn around = 48-40 = 8 people
Do not understand can ask, help please adopt, thank you!

If real numbers x and y satisfy x2 + 4y2 = 4x, then the value range of S = x2 + Y2 is______ ．

From x2 + 4y2 = 4x, y2 = 14 (4x − x2), from y2 = 14 (4x − x2) ≥ 0, the solution is 0 ≤ x ≤ 4, substituting s = x2 + Y2, s = x2 + 14 (4x − x2) = 34x2 + x = 34 (x + 23) 2-13, X ∈ [0,4], s monotonically increases on [0,4], when x = 0, s gets the minimum value of 0; when x = 4, s gets the maximum value of 16, so the