On Monday, the weather was fine, and Jinguancheng No. 17 Middle School.

In the classroom of the 11th class of junior high school.

Li Jie sat beside Xu He, his eyes were aimed at Xu He, and from time to time he was looking outside the classroom.

Xu He sat in his place, doing math problems seriously.

This is a problem of solving a system of ternary equations, a curly brace followed by three equations, which are a+2b-4=0, 2b+c=0 and a-4b+c=0, to solve this system of ternary equations.

This topic is relatively simple for Xu He, and recently their mathematics teaching progress happens to talk about the knowledge points of this ternary system of equations. Recently, Xu He has studied very well and listened to the lectures very seriously, and this topic is really simple for him.

The following series of ternary equations are relatively simple to solve.

This is tonight's math homework, and Xu He will use this spare time to complete the homework now, so that he will have more time to practice heading after school.

So, at this time, he had to solve the problem seriously.

Soon, Xu He came up with the answer to this question, a=3, b=1/2, c=-1.

In addition to this problem, there are many similar solutions to ternary systems of equations, and these problems are quite simple. The most important one is followed by two more questions, which can also be called application questions.

The title of one of the questions is as follows:

Xiaohong went to a clothing mall to conduct a social survey and learned that in order to motivate the enthusiasm of salesmen, the mall implemented the method of "total monthly income = basic salary + piecework bonus", and obtained the following information:

Salesperson A: 200 pieces of monthly sales, total monthly income of 3400 yuan;

Salesperson B: 300 pieces of monthly sales, total monthly income of 3,700 yuan;

Assuming that the monthly basic salary of the salesperson is X yuan, the reward for each piece of clothing sold is y yuan.

(1) Find the values of x and y;

(2) In order to sell more clothing, the shopping mall recommends a purchase method to customers: if you buy 3 pieces of clothing A, 2 pieces of clothing B, and 1 piece of clothing bag of C, it costs 390 yuan: if you buy 1 piece of clothing A, 2 pieces of clothing B, and 3 pieces of clothing C, it costs a total of 370 yuan. How much does a customer need to buy a piece of clothing A, B and C?

This is also the application of a system of ternary equations to solve the problem.

Because this is an exercise behind this knowledge point, it must be solved with the newly learned knowledge.

Therefore, this question is actually not difficult for Xu He.

Xu He slowly wrote down the process of solving the problem step by step in the homework book, looking very serious and careful.

Li Jie frowned, couldn't stand it anymore, couldn't help but reach out and knocked on Xu He's desk, and said, "Eh, I said that you really don't worry at all and don't worry at all?" Still have the leisure to do your homework here? ”

Xu He raised his head and glanced at Li Jie, then lowered his head and said while doing his homework, "What do I have to worry about?" ”

Li Jie stared at Xu He tightly and said, "You really don't care about the list of the school team at all?" ”

Of course, Li Jie also knows that Xu He will basically not be defeated. However, does Xu He really not care about the new school team list at all, and doesn't want to know at all?

At this time, Xu He has already solved the answer to the first question of this question, x=2800, y=3.

He put down the pen in his hand, looked up at Li Jie, and said, "I'm naturally very curious about the list of this school team, but can't this list be known until school ends in the afternoon?" What's the use of being in a hurry now? ”

Li Jie was really speechless, and said: "You can hold it down, you don't know that Lin Xuefeng has come up to ask twice." You haven't asked once. ”

Xu He smiled and said, "Can I see the list now if I ask?" ”

Li Jie was stunned and couldn't say anything.

Seeing Li Jie's appearance, Xu He smiled and said, "Look, you also know that you can't see it, so what do I have to ask?" Let's just wait honestly and find out when school ends in the afternoon. No, school is close now. ”

Li Jie gave Xu He a thumbs up, quite admired, and you can hold it steady.

It's only the morning school, and it's still early in the afternoon.

Now it's only the last class, and then it's time to end school for lunch.

At this time, Li Jie was already hungry, so he waited for the end of school and went to the cafeteria to grab a favorable position. Yes, eating at school is more like fighting, and when school ends at noon, everyone in the whole school rushes out, and almost more than half of them rush to the cafeteria at the same time. At that time, whoever ran the fastest would be able to eat earlier.

Therefore, the only thought of the students is that the teacher of the last class in the morning should not delay the class.

Once the hall is delayed, everyone can only eat the leftover dishes when they go to the cafeteria, and many dishes will be sold.

Now, Li Jie's mind has flown to the cafeteria.

Li Jie suddenly asked, "Eh, Lao Xu, what are you going to eat at noon today?" ”

Xu He was stunned for an instant, why did you have such a big span of this question?

Didn't we just talk about the varsity roster? Why did it suddenly change to what to eat at noon? Will it change to how to solve this math problem after a while?

Xu He looked at Li Jie, really a little speechless.

Being stared at by Xu He like this, Li Jie also felt a little embarrassed, he immediately raised his hand and said, "I'm sorry, I won't say it, okay?" I won't say anything, you write your homework well! ”

Xu He glanced at Li Jie, and then quickly answered the second question of this question.

As soon as I put down my pen, the class bell rang.

After a while, Xia Yu, the teacher of the last class of the morning, walked in. Yes, the last class this morning was a Chinese class again.

Xia Yu walked in and stretched out his hand to signal that the students didn't need to stand up, and then he said, "Before class today, I will announce something. ”

Everyone looked up at Xia Yu, I don't know what this person is going to do today?

Xu He also looked at Xia Yu, Xia Yu said: "Next Friday, the semi-finals of the National New Concept Essay Contest for Middle School Students will begin, and I will be the instructor of our Jinguancheng No. 17 Middle School participating team, and I will personally lead this participating group to Kyoto to compete." Xu He, prepare well, and we will set off together next Friday! ”

Everyone turned their heads to look at Xu He, their eyes full of envy.

Xu He: I'm going to Kyoto!

It's a free tour.

The whole class looked at Xu He with envious eyes, and they really wished that they could go to Kyoto instead of Xu He.

However, Xu He pouted slightly, a little reluctantly.

Seriously, Xu He really doesn't want to go to Kyoto. Because if he goes to Kyoto, he will probably miss the league game. Now it's time for the league to sprint, and leaving at such a critical moment, Xu He can't rest assured.

However, there is no way, this Xu He really can't refuse.

Because of this incident, the school had already notified the parents of those participating students, and Xu He's mother Tang Qian had already known about it. If Xu He said that he would not go, his mother Tang Qian would definitely take action against Xu He to implement Huang Jingtiao education.

And it is unlikely that the school will agree to Xu He's refusal, at least the teacher Xia Yu in front of him will not agree.

Therefore, Xu He really has no right to refuse.

Xu He bowed slightly, and reluctantly replied, "Got it, teacher!" ”

When the whole class saw this, they rolled their eyes, they felt that Xu He was too pretending. Obviously, he wanted to go very much, but he had to pretend that he didn't want to go on the surface, as if the school forced him to go.

Disgusting!

Especially those students with good academic performance, even more so.

They were very angry, very uncomfortable.

Not to mention that this damn Xu He robbed them of their places, he also pretended to be like this, which is simply an insult to them. They stared at Xu He through gritted teeth, clenched their fists, and said fiercely in their hearts: "Don't be complacent, next time we will definitely surpass you, so that you can't go." ”

To be honest, Xu He really didn't want to go.

Li Jie immediately stretched out his hand and touched Xu He and said, "Eh, old Xu, you are a little too much, you still think about whether the study committee members are in a good mood, you are like this, I am afraid that you will be beaten up." ”

Xu He shrugged his shoulders and felt innocent.

He really didn't want to go, but he couldn't help it.

After this incident passed, Xia Yu began today's teaching content, and the time of a class passed quickly, and it passed quickly. The students in the eleventh class of junior high school were all staring at Xia Yu tightly, and they were calculating the countdown in their hearts.

Teacher, it's almost time for school to end, you can talk quickly, don't delay the class.

Yes, at this time, many students' minds flew to the cafeteria. If we drag the hall, we won't be able to eat well at noon today.

It's in a hurry, it's urgent!

Now Li Jie is very anxious, his butt has already left the chair, and he is ready to rush out of the classroom and kill in the cafeteria.

Xia Yu saw the appearance of the students below, he chuckled lightly and said, "That's all for today's class, I know that your thoughts have already flown to the cafeteria." I won't stop you, get out of school! ”

Two minutes early, Xia Yu got out of class two minutes early.

The male classmates of the eleventh class of junior high school stood up in a swarm, rushed out quickly, and rushed to the cafeteria, as if they were being dragged to the hall, the speed was really too fast, Xia Yu was startled, and then smiled slightly bitterly.

Xu He didn't expect these classmates to be so sharp, they all seemed to be hungry and crazy.

Really, it's like the start of a 100-meter trapeze battle, rushing out one by one, and the posture is really scary.

Xu He was not like these guys, but he slowly walked out of the classroom and walked slowly to the cafeteria. When he came to the cafeteria, Li Jie had already helped him cook, no wonder this guy was unhurried.

But Li Jie was very fierce, and he rushed out at once, and the speed was really fast.

Xu He felt that if Li Jie also had such a fast speed in the game, then Li Jie would be amazing.

Xu He casually ate some food in the cafeteria, and then he would go back to the classroom and finish the afternoon class. Then he immediately rushed to the playground and rushed to the new roster of the varsity team.

Because Coach Yang Tong Mingxiong has said in advance, the list of members of the new school team will be posted at the door of the school playground. So Xu He walked to the playground as soon as they got out of school to see the list.

Xu He also wants to see who are the candidates for the school team this time?