There are 3600 science and technology books and story books in the school, of which 80% are science and technology books. How many are science and technology books and story books?

The story book has
3600 ÷ (1 + 80%) = 2000
Science and technology books
2000 × 80% = 1600

There are 280 story books, equivalent to 4 / 7 of the number of science and technology books?

280 divided by 4 / 7 is 490

The solution of the limit of work number function
Can you be more specific

Common methods:
1. Direct substitution
2. Elimination method. (rational function, type 0 / 0)
3. The highest power of division denominator (rational function, when the highest power of numerator ≤ the highest power of denominator)
4. First find the limit of the reciprocal, and then use the relationship between infinitesimal and infinity
4. Rational denominator
5. Derivation of compound function
6. Law of Robida
If you give examples, there are too many. You can look for examples in the textbook. Or Baidu, there should be a lot of information. Or you can leave me a contact information. I can send you some

Xiao Wang and Xiao Zhao are reading together in the library today. It is known that Xiao Wang goes to the library once every three days and Xiao Zhao goes to the library once every seven days. They will go to the library next time

A is a positive definite matrix and B is a real matrix. It is proved that the square of a multiplied by the square of B = the square of B multiplied by A

There is a problem with this topic. For example, take B = I_ N can't deduce a ^ 2 = a

What... Do you like best?

You can ask a countable noun or use an uncountable noun, depending on what you want to ask
This is best, so it's usually singular, favorite
Eg: what sport do you like best
Hope to help you~

If EF: FG = 5:9, find the perimeter of efgh

Let EF = 5x, then he = 9x, ∵ rectangle efgh is inscribed in △ ABC and ad ⊥ BC ≁ eh ∥ BC, EF ∥ ad ∽ AEH ∽ ABC, △ BFE ∽ BDA ≁ hebc = aEAb, efad = BEAB, that is, 9x48 = aEAb, 5x16 = BEAB, ≁ 9x48 + 5x16 = aEAb + BEAB = ABAB = 1

English translation
Consumer tastes and preferences
Distribution channels
Values system
Business system
Legal regulations

Consumer tastes and preferences
Distribution channels
Values system
Business system
Legal regulations

In the cube abcd-a'b'c'd ', e is the midpoint of CC' and F is the midpoint of BB '
The original question on the paper is like this. I looked at the figure below. F is the midpoint of b'd '

Is there something wrong with your topic? According to your topic, EF does not intersect with ab'd ', is f the midpoint of AA'
If so, you can build a system with vectors. Or you can confirm the next question before I can answer

Make tea composition 30 words
There are also three sentence forms

The best way to make tea is to use an electric kettle to boil the water.
The advantage is the water is actually boiling when you pour it over the tea,either in a cup or in a teapot.
This helps to extract the most flavor from the tea,and it reduces the length of time you need to brew the tea.
The longer you brew,the more bitter tasting tannin will be dissolved.
An electric kettle is found in almost every home in Europe for this reason.Heating water in the microwave is slower,more dangerous and produces inferior tea.
This is why we sell hundreds of electric kettles every month.
You will also get better results using loose tea in a teapot,rather than teabags.Loose tea is not ground as fine as the tea in tea bags,as it has more room to circulate in the pot.The finer tea is ground the more bitter tannin is released.Use a tea strainer to avoid getting tea leaves in your cup.
The British style 3.1 gram teabags have 50% more tea than the US style string and tag 2.1 gram teabags.The teabags are larger and so the tea has more room to brew.
Loose leaf tea brewed in a teapot makes the best tasting tea.
We recommend one teaspoon of loose tea per person,plus one for the pot.
Use freshly drawn water.When water is re-boiled,or stands for a while,it loses oxygen which prevents the full flavor of the tea being released.
Warming the pot first.This helps the brewing process by maintaining the brewing temperature for longer,to extract more flavor from the tea.
Be sure to use boiling water to make the tea.Water which is "off the boil" does not allow the tea to brew properly.
Brewing for 3-5 minutes,shorter times will not reveal the full flavor and the quality of the tea.Longer brewing will result in a bitter tasting tea as Tannin will start to be extracted from the tea leaves.
Stir the tea in the pot once or twice while it is brewing.
Tea bags – the same directions

There are 3600 science and technology books and story books in the school, of which 80% are science and technology books. How many are science and technology books and story books?