Write down 5 rules (2 sentences) that the library must abide by in English Except laeve your bags in the left bag place Don't spesk loudly. Don't disturb others.

Don't eat or drink.
Don't play games.

According to the context, the meaning of "those who can't read until they have a library will not read even if they have a library"

If you don't have it, you hope to have it, and you will cherish it. But once you do, you will naturally ignore it, thinking that if you have it, you don't have time to go now, and you can find time later

On a map with a scale of 1:5000000, the distance between a and B is 2.5cm. What is the actual distance between a and B?

A: the actual distance between a and B is 125 km

Given that the real number x satisfies the equation | x-3 | + | x + 3 | = - 2x, find the range of X

If x ≥ 3, then x-3 + X + 3 = - 2x, then x = 0, not true
If x ≤ - 3, then 3-x-x-3 = - 2x, then it is true
If - 3 < x < 3, then 3-x + X + 3 = - 2x, then x = - 3, not true
In conclusion, X ≤ - 3

The difference between a and B is 80, 1 / 2 of a is equal to 2 / 3 of B. what are the two numbers? The arithmetic solution

The difference between a and B is 80, 1 / 2 of a is equal to 2 / 3 of B. what are the two numbers? The arithmetic solution
A80 (1-1 / 2 / 3)
=80÷（1-3/4）
=80÷1/4
=320
B 320-80 = 240

Application of mean inequality in practice
If x + 2Y = 30, find the maximum value of X * y

X*2Y

5. A truck is driving from a to B at the speed of 50 km h, and a car is catching up 90 km away from a,
Three hours later, I caught up with the truck on the way to find the speed of the car

Car speed: (90 + 50 × 3) △ 3 = 80 km / h

It is known that the equation of the line where the three sides of ABC lie is ab: x + 2Y + 2 = 0 BC: 2x-y-6 = 0 AC: x-2y + 6 = 0

AB：x+2y+2=0,BC：2x-y-6=0,AC：x-2y+6=0,
——》Point a is (- 4,1), point B is (2, - 2), and point C is (6,6),
——》The coordinates of the midpoint of AB are (- 1, - 1 / 2),
The slope of the line AB: KAB = - 1 / 2,
——》The slope of the vertical line ab k'ab = - 1 / KAB = 2,
——》The vertical equation of the line AB is y + 1 / 2 = 2 (x + 1),
Similarly, the coordinates of the midpoint of BC are (4,2),
The slope of the straight line BC: KBC = 2,
——》The slope of the vertical line k'bc = - 1 / KBC = - 1 / 2,
——》The vertical equation of the straight line BC is Y-2 = - 1 / 2 (x-4),
The intersection of the vertical lines in the straight lines AB and BC is the center O of the circumscribed circle,
——》The coordinates of the center o are (1,7 / 2)
r^2=OA^2=[(1+4)^2+(7/2-1)^2]=125/4,
——》The equation of circumscribed circle is: (x-1) ^ 2 + (Y-7 / 2) ^ 2 = 125 / 4

The passenger car and the freight car leave from the two places at the same time. When they meet, the distance ratio between the passenger car and the freight car is 5:4. After they meet, the freight car is 15 kilometers faster than the passenger car
It is known that the freight car has been traveling for 10 hours. How many kilometers is the distance between a and B

Let the speed of the bus be x, the speed of the train before meeting be y, and the speed after meeting be (y + 15). The total distance can be expressed as 10 * X
Then the equation x / y = 5 / 4, (4 * 10x) / (9y) + (5 * 10x) / (9 * (y + 15)) = 10
Simplify yourself and ask if you don't know

A problem of projective plane geometry
Tell you a conic, there are three points on the conic
The three points are (1,0,0), (0,1,0), (0,0,1)
Then the epipolar line of a point (3,2,1) is [3,2,1]
Can you still find some properties of this curve?
Find as much as you can
You are told that a certain concern is on the three points
（1,0,0）,（0,1,0）,（0,0,1）and that the polar
line of （3,2,1）is [3,2,1].What more can you say
about the conic?
This is a geometric problem of projective plane
Conic: curve
Polar line: polar line
I will offer the highest reward I can give, and thank you after the answer

The matrix of 3 * 3 is a B DB c ed E F, AXX + cyy + fzz + 2bxy + 2dxz + 2eyz = 0 (1,0,0), (0,1,0), (0,0,1), so the matrix of a = 0C = 0f = 03 * 3 is reduced to 0, and the formula of a B DB 0 ed E 0 is reduced to bxy + dxz + eyz = 0

Write down 5 rules (2 sentences) that the library must abide by in English Except laeve your bags in the left bag place Don't spesk loudly. Don't disturb others.