If you observe things around you carefully, there are many phenomena that make us curious. Please list 2 examples that you are most interested in and ask questions you want to know Pour more than half a glass of water into a glass, and then continuously add salt, and stir it with a glass rod. It is found that after adding a certain amount of salt, the added salt no longer dissolves. What scientific conclusion can you draw from this experimental phenomenon? In a small mountain village with green mountains and beautiful scenery, in order to drive the villagers to become rich, villager Xiao Zhang set up a paper mill by the river. A few years later, many villagers have become rich. However, the river is no longer clear, but becomes turbid and smelly. Please talk about this phenomenon Note: those who answer this question within today include the reward score, plus 10 points (the answer must be to my satisfaction)

When combing the hair, when the comb leaves the hair, the hair will be close like the comb. I want to know why this happens
When you brush the glass at home, it's difficult to separate the two pieces of glass when there is water between them
There is a limit to the amount of salt that can be dissolved by a certain amount of water. That is to say, salt has a maximum dissolution point in water
When we make use of resources to make a fortune, we should consider the problem of sustainable development. We can't ignore the environment and other factors because of a little profit. This is not worth the loss

Section 5, Chapter 2, Grade 7, lower a, science exercise book

Gravity attraction ratio g = mg mass gravity 9.8n/kg spring dynamometer 490 curve motion gravity vertical downward projectile weight motion state vertical downward vertical weight vertical line horizontal vertical cdbb
I'm sorry for the tenth question. You have to draw it yourself
11.G=mg=150kg*9.8N/Kg=1470N
m=G/g=0.0196N/0.98N/Kg=0.002Kg
0.002kg=2g
D
Mass: 0.10.20.30.4
Gravity: 1 2 3 4
Now I'm sorry, you have to draw by yourself
You must choose me. I finally found this exercise book and called you

Three questions in the expansion and improvement of the third page

Hello, classmate
You should be asking about the assignment book a with a purple cover
Development and improvement
(1) By analyzing the volume and mass change ratio of 1 and 2 (2 and 3, 1 and 3) or 4 and 5 (5 and 6, 4 and 6) in the above table, we can conclude that (the mass to volume ratio of the same substance is a constant)
(2) By analyzing the experimental relationships (1 and 4, 2 and 5, 3 and 6) in the table, we can conclude that the mass of a and B liquids with the same volume is different
(3) By analyzing the mass volume ratio of liquid a and liquid B in the above table, we can conclude that the mass volume ratio of the same substance is the same, and the mass volume ratio of different substances is generally different
We have done these questions, and the teacher has told us the correct answer, hope to help you!

Grade 6 Volume 1 mathematics book 105 page 1, 2, 3, 5 1 question 5 points

（1）
125 × 44% = 55 (pieces)
125 × 20% = 25
125 × 36 = 45
55 × 1 + 25 × 0.5 + 45 × 0.1 = 72 yuan
（2）
20 × 85% × 3 = 51 yuan
(3)
7600×(1-10%)×(1-10%)
(5)
The first question: 1500 × 4.68% × 2 × 5% = 7.02
Question 2: 1500 + (140.4-7.02)
Due to the time problem did not write answer, please understand

Mathematics Grade 6 Volume 1: question 8 on page 102, question 9 on Page 103 and question 5.6 on page 105

P102.8
80000 x 96% = 76800 yuan
2.76800x1.5% = 1152 yuan
P103.9
1.300x5.04% x3x (1-5%) = 46.7 yuan
2.300x5.4% x3x (1-5%) + 300 = 346.7 yuan
P105.5
1.1500x4.68%x2x（1-5%)=133.38
2.1500+133.38=283.38
6.1 it can support national construction, ensure deposit safety and order, and increase some income
2. When you withdraw money, you pay more interest to the bank. The ratio of interest to principal is called interest rate. The interest paid by 5% is interest rate
I hope I can help you!

Answers to 6 questions on page 102 of Mathematics (people's education)

(1) 20000 × 3.24% × 3 = 1944 yuan
20000 + 1944 = 21944 yuan
(2) 1944 × 5% = 97.2 yuan

Super fast ~! Solution of equations y-10x = 30% Y Y-10 (x + 6) = 10% Y

Y-10x = 30% Y-10 (x + 6) = 10% Y
0.7y=10x①
0.9y=10x+60②
Subtraction of two formulas
0.2y=60
y=300
Substituting (1)
210=10x
x=21

Solving equations x + 1 / 6 = y + 1 / 8 = x + Y / 10

(1) (x + 1) / 6 = (y + 1) / 8 cross multiply by 8 (x + 1) = 6 (y + 1) to get (3) 4x-3y = - 1
(2) (x + 1) / 6 = (x + y) / 10 cross multiply by 6 (x + y) = 10 (x + 1) to (4) - 2x + 3Y = 5
(3) Add to (4)
2x=4
Substituting x = 2 into (4)
3y=5+2x=5+4=9
y=3

The equations y △ 10 + X △ 12 = 5 △ 6, X △ 10 + y △ 6 = 43 △ 30
The first one should be y / 15 + X / 12 = 5 / 6.

Y / 15 + X / 12 = 5 / 6 two days at the same time multiply by 60 to get 4Y + 5x = 50, marked as ① X / 10 + Y / 6 = 43 / 30, both sides also multiply by 30 to get 3x + 5Y = 43, marked as ② × 5 - ① × 3 to get 25y-12y = 215-150, the solution is y = 5, y = 5 into ① to get x = 6, so the solution of the original equations is x = 6, y = 5

Solve the equations 10 (X-Y) = 3 (x + y) + 156 (x + y) = 4 (2x-y) + 16
10（x-y)=3(x+y)+15
6(x+y)=4(2x-y)+16

It's better to do it slowly, such a simple formula