Xiao Ming and Xiao Hong both go to the library to borrow books. Xiao Ming goes every three days and Xiao Hong goes every five days. They went to the library together on July 1. The next time they will meet again in the library on July 1

Xiao Ming and Xiao Hong both go to the library to borrow books. Xiao Ming goes every three days and Xiao Hong goes every five days. They went to the library together on July 1. The next time they will meet again in the library on July 1

3. The least common multiple of 5 is 3 × 5 = 15 days
1+15=16
Next time they will meet again in the library on July 16

Three classmates discussed going to the library to borrow books in summer. Xiao Ming said, "I go every four days." Xiao Hua said, "I go every six days." Xiao Hong said, "my home is far away. I can go every 10 days, but I can borrow more books each time." if three people go to the library to borrow books at the same time on July 5, then at least in a few days, two of them will meet in the library?

4 = 2 × 2, 6 = 2 × 3, 10 = 2 × 5, so the least common multiple of 4 and 6 is 2 × 2 × 3 = 12; the least common multiple of 4 and 10 is 2 × 2 × 5 = 20; the least common multiple of 6 and 10 is 2 × 3 × 5 = 30; because 12 < 20 < 30; so it will take at least 12 days for two of them to meet in the library; a: it will take at least 12 days for two of them to meet in the library

How much does a cubic stone weigh

According to the density of the stone, a cube is exactly two tons, but other objects depend on the density

3\5{1\3[-3\4-(4\3-1)-x\2-3\4]-3\4]-3\4+5}=1-2\5x x=?

Multiply by 5 on both sides
3{1\3[-3\4-(4\3-1)-x\2-3\4]-3\4]-17\4}=5-2x
-3\4-(4\3-1)-x\2-3\4-3\4-51\4=5-2x
-1\3-x\2-3\4-57\4=5-2x
3x\2=61\3
x=121\9

It is known that the height of the cylinder is 5 decimeters. If the cylinder is divided into two equal halves vertically through the center of the bottom surface and the surface area is increased by 60 square decimeters, the volume of the cylinder is 5 decimeters______ Cubic decimeter

The radius of the bottom surface is: 60 △ 2 △ 5 △ 2 = 3 (decimeter), the volume of the cylinder is: 3.14 × 32 × 5 = 141.3 (cubic decimeter); answer: the volume of the cylinder is 141.3 cubic decimeter. So the answer is: 141.3

The sum of a number and 2 / 9 is equal to 28% of 27 / 9. What is the number?
The sum of a number and 2 / 9 equals 28% of 2 and 7 / 9. What's the number?

Let this number be X
x+2/9=2^7/9×28%
x+9=7/9
x=5/9

Ask a few very simple math problems, high school things all back to the teacher
(1) Y = 1 / x2-1 for the range (2) y = 1 / x2 + 1 for the range (3) y = 1 / x + 1 for the range (4) y = 2x + 4 / 4x + 8 for the range (5) y = 3x / 2x + 1 for the range is very basic, more than one problem to solve more than ten

1. Y is not equal to 0
2、0

Given that the opposite number of a is 2 and the reciprocal of B is - 1.5, find the value of a + 3b of 2b-a

a=-2
b=1/(-1.5)=-2/3
So the original formula = (- 2-2) / (- 4 / 3 + 2)
=-4/(2/3)
=-6

In this paper, we define two new operations: O and O. for any rational number a, B, there are a, B = a + B-1, a, B = AB-1?
narration
```Junior one knowledge bar```
```The process must be narrated```

That is, a 0b = a + B-1, a ● B = AB-1
（6○8）●（3○5）
=（6+8-1）●（3+5-1）
= 13●7
= 13*7-1
=91-1
=90

What's 25 out of 4 times 3.14

13.345