Mathematics Rapid !!!! I hope to explain each step so that I can understand it easily. ）

Let Xiao Ming use m for a day, and use 1 m of pocket money every day

Sister n days, 1 n per day

then 3 m+4 n=1 4

4/m+3/n=1/3

The solution yields 1 m = 1 12

1 n=0 (meaningless).

When n tends to infinity, 1 n tends to 0

So Xiao Ming spent it in 12 days alone, and his sister didn't seem to spend money.

Xiao Ming 3 days + sister 4 days = 1 4

Xiao Ming 4 days + sister 3 days = 1 3

Xiao Ming 1 day + sister 1 day = (1 4 + 1 3) 7 = 1 12 Xiao Ming 3 days + sister 3 days = (1 12) x 3 = 1 4 Xiao Ming 1 day: 1 3-1 4 = 1 12

sister 1 day; 1/12-1/12=0

For some reason, I couldn't figure it out. = =、

Solution: Xiao Ming spends x1 yuan a day, and his sister spends x2 yuan a day, with a total of Y yuan.

It is derived from the title:

3x1+4x2=y/4

4x1+3x2=y/3

Simplification: 12x1+16x2=y

12x1+9x2=y

16x2=9x2, the equation does not hold. There is no solution to this question.

Let Xiao Ming use x yuan a day, and my sister uses y yuan a day. There are m dollars in total.

As can be seen from the title, 3x+4y=m 4 . 1

4x+3y=m÷3 。。2

Combine 4 to get 12x+16y=m

Equation 3 yields, 12x+9y=m

Subtract the two formulas.

y=0 x=m÷12

That is, the younger brother can use it alone for 12 days.

The method is the elimination method (uh, your question is not wrong. Sister with 0 yuan? ）

Because the area of the three-rent old angular abc is 1, so the xy=2 in the point A and because the point A is on y=m x, the disadvantage of the silver rise is m=2 straight line y=x+1

The coordinates of point A are (1,2).

When y=0.

x = -1 and the length of the socks is 3 in BC

Because AB is 2 in length

So the triangle abc area is 3

1,42,（0,0）

3, (1, root number 3 2).

4,b(2 times the root number 3,2)c(,5 times the root number 3 2)5,o(2,0) or there is a wait, you write it first.

Hehe, I'll do it.

3.（-1.Root number 3).

4.(2 roots, number 3,2) This is more difficult, the trigonometric functions are almost forgotten, let's do the math yourself, anyway, you have to add a corner.

5.There are 4 answers to this theory, since you don't know which ab side you are, only count the two sides of up and down = 8 ((23 5,0)

You'd better do it!

If not, ask the teacher!

If you let others help you with this kind of topic, I'm afraid you won't know anything in the future.

258÷(1+

A: The population in 1998 was 2.4 million.

In 2018, it was 256 (

So it's not equal.

Divide by population: 258 multiplied, so it's not the same.

1 Assume that the population was x ten years ago

x*(1+x=2,400,000.)

258* (ten thousand.

So different.

There's really nothing wrong with your question.

It's just that I'm just in high school, and I'm not very used to high school, especially the way high school teachers teach.

In addition, the pace of the teacher's lectures is relatively fast, and I always feel that I can't keep up.

Take your time, don't be too anxious, just listen carefully to the lecture and you'll be fine later.

Do not worry.

Do more questions, find patterns, and summarize more.

I still agree to read more mathematics textbooks, because there are the most basic principles, the origin of the formula, first of all, we must understand this further before we can use and do problems, and then we should do more questions, and ask teachers and classmates if you don't understand it, don't be shy. In high school, you should maintain a good attitude, have a normal heart, learn more from your classmates around you, and learn from their good study methods. There is also the need to work hard, cherish time, and seize the time.

Study when it's time to study, and rest when it's time to relax. Don't think that your classmates' grades are so good, in fact, you just don't see them working hard, just like when someone sees others being rich and rich, they envy others, but they don't see that others have worked hard, worked hard, and pretended to be grandchildren! This is my experience, and I am here to tell you all about it, even though we don't know each other, I hope it will help you.

There is indeed a certain difference between middle school math and high school math. High school math needs to do more practice questions to help understanding. But too many dead questions are not good, you must understand the reason, or ask a one-on-one tutor, maybe it helps.

1100*(1-15%)=935 so you can buy.

500 kg of paddy is needed.

Solution: 1100 (1-15%) = 1100*

Because 935>880

So you can buy a ticket for 880 yuan.

The smallest natural number is 1The minimum composite number is 4The minimum prime number is 2It is not a prime number nor a composite number.

So it's 1421 or 1420

The smallest natural number is: 1

The smallest composite number is: 4

The smallest prime number is: 2

Neither prime nor composite is: 1

Then the number is: 1421

This four-digit number is definitely 1421, 1420 is not right.

The wind blows the willows out of the wall branches, and what he said is right. I'm going to help you revisit the definition, the definition range of composite numbers and prime numbers is positive integers, that is, composite numbers and prime numbers describe the properties of positive integers. Determine whether a number is a composite or prime number, provided that the number is a positive integer!