Is zero a natural number Just answer yes or no

Is zero a natural number Just answer yes or no

Not before 85, but after 85

It is known that the absolute value of the solution of the linear equation x-2k / 5 = 1-kx-1 / 3 with respect to X is 1
It is known that the absolute value of the solution of the linear equation x-2k / 5 = 1-kx-1 / 3 with respect to X is 1.

There are two ways to solve this problem
Method 1. According to the known formula, we can first find the analytic formula of X with respect to K, that is
x=（6k+10)/(15+15k)
Because the absolute value of X is 1, x = ± 1
So, when x = 1, (6K + 10) / (15 + 15K) = 1
The solution of the analytical formula is as follows
k=-5/9
When x = - 1, (6K + 10) / (15 + 15K) = - 1
The solution of the analytical formula is as follows
k=-25/21
Method 2. Because the absolute value of X is 1, x = ± 1
Take x = 1 and x = - 1 into the original formula respectively
1-2k/5=1-k-1/3.(1)
-1-2k/5=1+k-1/3.(2)
Solutions (1) and (2) are obtained respectively
k=-5/9
k=-25/21

Fifth grade volume two find the law of mathematics ppt

Given three adjacent natural numbers, the sum of two numbers must be even. Why?
Drawer principle solution

Any three adjacent natural numbers must be even, odd, even or even odd, then the sum of the two numbers in the former case and the latter case must be even. (odd + odd = even, even + even = even)

The third root of (35)

≈3.27106631

There is a batch of goods in the warehouse. The weight ratio of the far away goods to the remaining goods is 2:7. If another 64 tons are transported, the remaining goods are only three fifths of the original goods in the warehouse
How many tons of original goods?
Do not use equation solution, copy search

2 / (2 + 7) = 2 / 9
Another 64 tons, 1-3 / 5 = 2 / 5 of the total
Original: 64 (2 / 5-2 / 9) = 360 tons

Finding monotone increasing interval of function y = 3sin (π / 3-2x)

y=3sin(π/3-2x)
=-3sin(2x-π/3)
Monotonically increasing for 2x - π / 3 ∈ (2k π + π / 2,2k π + 3 π / 2)
So the monotone increasing interval is:
x∈(kπ+5π/12,kπ+11π/12) k∈Z
If you still have doubts, please ask

As many as possible,

37. Give a pile of oranges to several children. If everyone has three oranges, there will be eight more oranges. If everyone has five oranges, the last person will get at least three oranges. How many children and how many oranges are there?
With a child, there are 3A + 8 oranges
According to the meaning of the title
5≥3a+8-5（a-1）≥3
5≥3a+8-5a+5≥3
-8≥-2a≥-10
4≤a≤5
A = 4 or 5
So there are four or five children
There are 20 or 23 oranges
38、
A school held a campus singer competition. The competition was held in a lecture hall with a maximum capacity of 300 people. There were 56 singers, judges, teachers and guests. In order to set off the atmosphere, the number of participants should exceed 85% of the total number. Do you know how many students can at least watch it?
There are a student to watch
According to the meaning of the title
（a+56）/300>85%
a+56>255
a>199
At least 199 students
39. After improving the working method for the first time, each worker processes 10 more parts per day than before, so each worker processes more than 200 parts in 8 days. After improving the working method for the second time, each worker makes 27 more parts per day than after the first improvement. In this way, the average number of parts per worker is more than that of the previous 8 days in only 4 days, How many parts did each worker process every day?
Suppose every worker makes x parts on average every day
According to the meaning of the title:
8(X+10)>200===》X>15
4(X+10+27)>8(X+10)====>X

If 67 tons of goods are moved from warehouse A to warehouse B, the goods in warehouse A are twice as much as those in warehouse B; if 17 tons of goods are moved from warehouse A to warehouse B, the goods in warehouse A are five times as much as those in warehouse B. how many tons of goods are stored in the two warehouses?

Suppose that there are x tons of goods in warehouse B, and the goods in warehouse A are two times as much as those in warehouse B by moving 67 tons of goods from warehouse A to warehouse B, then the goods in warehouse A are 2x + 67 × 3. From the meaning of the title, we can get the following: & nbsp; 2x + 67 × 3-17 = 5 (x + 17), 2x + 201-17-2x = 5x + 85-2x, & nbsp; & nbsp; & nbsp; 3x + 85-85 = 201-17-85, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 3x = 99, & nbsp; &A: the original goods in warehouse A and B are 267 tons and 33 tons respectively

In a subtraction formula, the sum of the subtracted and the difference is 868, and the known difference is 25 less than 8 times of the subtraction

Subtracted = subtracted + difference
So the sum of three numbers is equal to two times the subtracted number
Subtracted = 868 / 2 = 434
The sum of subtraction and difference is also 434
If you add 25 to the subtraction, it is exactly 8 times the difference, so 434 + 25 = 459 is 8 times the difference + 1 times the difference = 9 times the difference;
Then the difference = 459 / 9 = 51
Then the subtraction is 434-51 = 383