Sequence 1,5,9 The general formula of is ()

Sequence 1,5,9 The general formula of is ()

4n－3

Nanometer is a unit of length, which is used to represent tiny units. One nanometer is one billionth of a meter, which is equivalent to 60000 times the diameter of a hair
If someone has 50000 hairs, what is the sum of the diameter of the 50000 hairs_______ Rice

3 meters

The first volume of the first grade of junior high school (people's Education Edition) 3.4 practical problems and all the problems and formulas of one variable linear equation

The problem of sum, difference, multiple and quotient: grasp the key words in the title: more, less, multiple, fraction, etc. exercise 1: the length of a rectangle is more than the width, and the known length is 6 meters

Positive integers are arranged according to the rule shown in the figure. If the number 2009 is the nth number from left to right in row m, then n / m=
one
3 2
4 5 6
10 9 8 7
11 12 13 14 15
.

Observation rule: 1 number in the first line, 2 numbers in the second line
p(p+1)/2

A piece of steel with a bottom area of 12 square decimeters and a weight of 702 kg is known to weigh 7.8 kg per cubic decimeter. How many decimeters is this piece of steel long?

702 △ 7.8 △ 12, = 90 △ 12, = 7.5 (decimeter), a: this steel is 7.5 decimeters long

Phrases in unit 4 of Volume 1 of Grade 8 English edition
Please bring the translation if you can. I hope it's not random

There are 160 red, yellow and white balls. If you take out 13 red balls, 14 yellow balls and 15 white balls, there are 120 left. If you take out 15 red balls, 14 yellow balls and 13 white balls, there are 116 left. How many red, yellow and white balls are there?

According to the above analysis, taking 160 △ 40 = 4 times just finished, red ball is still poor: 43-1 = 13, white ball is more than 1-45 = 15, yellow ball is finished; it shows that 13 of red ball is equal to 15 of white ball, the ratio of red ball to white ball is 3:5; according to the comparison of two schemes, it is found that 13-15 = 215 of white ball is more than 215 of red ball by 4; that is, white ball is more than red ball by 4 △ 215 = 30, so red ball has 30 △ 215（ 5-3) × 3 = 45; white ball has 45 + 30 = 75; yellow ball is 160-45-75 = 40; answer: (1) original yellow ball 40, (2) original red ball 45, white ball 75

How many feet is 68 cm around the waist
ditto!

100 cm is one meter, that is, three feet, so one foot is 100 / 3 cm, 68 cm is about two feet more

How much is one minus two-thirds of a primary school math problem?

If it is equal to one third, one can spend three thirds to reduce two thirds, so that you can see clearly!

One minus (one sixth plus five ninth) is equal to?

25 out of 18