I don t understand math problems, and there is a math problem that I don t know how to do

1) Set: The distance between the two places is x kilometers.

x÷100+x÷80+

x=200A: The distance between the two places is 200 kilometers.

2) Two cars meet x hours after the express train leaves.

100x+60×(x+32/60)=448160x=416

x = A: The two cars meet an hour after the express train leaves.

3) Answer engineering questions;

Set: A departs x hours and meets B.

1/2+1/3)x+1/3=1

5/6)x=2/3

x=4 5Answer: A departs 4 5 hours and meets B.

1. Set the distance x---x 100)+(1 2)+(x 80)=5---x=200km

Note: (x 100) is the time taken from A to B; (1 2) is 30min of rest; (x 80) is the time taken from B to A.

2. Set time x---x+32 60)*60+100x=448---x=3, time x, and the distance between the two places is a fixed value of 1---1 3) (x+1) + (1 2) x = 1---x=

Question 1: Suppose the distance is x

Then: x 100 + x 80 =

x=200km

Question 2: 448-60 * (32 60) = 416 km416 (60 + 100) = hours = 2 hours and 36 minutes. Question 3:

2 3 divided by (1 2 + 1 3) = hours = 48 minutes.

1.Go to the time t, come.

The distance to and from is equal.

100t=80(

t=2s=2*100=200

1.Solution: Let the distance be x

30min＝

t＝x/100+x/80=

x=200 ( is the divide).

Answer. 2.Solution: Set up the express train to meet x hours after departure

32min= 448-60*

60x+100x=412 x=

Answer. 3.Solution: Let the total distance be 1, the speed of A is 1 2, and the speed of B is 1 3

If B is known to have walked for 1 hour, then he has traveled 1 3 of the total distance first, and two-thirds of the distance remaining is divided by the sum of the speed of A and B, i.e.

2 3 divided by (1 2 + 1 3) equals 4 5, i.e. answer.

Summary. 1 kg - 999 grams = 1 gram.

Hello dear. What is your math problem? Take a screenshot and let me see if it's okay dear.

Circle that question, question 10.

1 kg - 999 grams = 1 gram.

1.The starting fare of a taxi is 6 yuan (the average charge is 6 yuan for those within 2 kilometers), and the fee for more than 2 kilometers is charged per kilometer. Teacher Wang Danzhu took a taxi for 5/2 of a kilometer, and if he traveled more than 5 kilometers, he should pay 14 yuan.

2.A bag originally contained 10 safflowers, and then 15 white flowers. If you touch any one of them, the probability of touching a safflower is 40%.

3.Of the three inner angles of a right triangle, the degree of the smallest angle is one-fifth of the degree of the largest angle, and this smallest angle is (d).

A: 30° B: 60° C: 45° D: 18°

4.A cube with a flute length of 1 meter has a volume of 1 cubic meter. If you cut it into small cubes with a flute length of 1 cm, you can cut it into 1,000,000 of these small cubes. Arrange these small cubes in a row, and the length is 10,000 meters.

5.The installation network in the Shenghu Garden Community has been installed in 250 households, and 6 out of 11 have not been installed. How many residents are there in this community?

250 (1-6 11) = 550 households.

6.A rectangular fiberglass with a length of 8 decimeters, a width of 6 decimeters, a height of 4 decimeters, and a water depth of decimeters. If you put a cube of iron with a flute length of 4 decimeters, how many liters of water will overflow from the glass tank?

4*4*4-8*6*(L.)

x²+y²=x²+2xy+y²-2xy=(x+y)²-2xy=a²-2b

x²-xy+y²=x²+2xy-2xy+y²-xy=x²+2xy+y²-3xy=(x+y)²-3xy=a²-3b

**I don't know how to ask me.

The square of x + the square of y = the square of (x + y) - 2xy = the square of a - 2b

The square of x - the square of xy + y = the square of (x + y) - 3xy = the square of a - 3b

(x+y) squared = x squared + y squared + 2*x*y; That is, the square of a = the square of x + the square of y + 2*b;

So the square of x + the square of y = the square of a - 2*b;

Because the denominator cannot be equal to 0, x-3 cannot be equal to 0 and x cannot be equal to 3

It's very simple, the denominator of f(x) is not zero, of course, x is not equal to -3, find the images of -4 and 1, that is, let you find the corresponding images of -4 and 1, that is, f(-4) and f(1), which are equal to 2 and respectively.

This means that if x=3 and the denominator is 0, right, then this function is meaningless......Then you take -4 and 1 into x, respectively, and find y.

Understand. Math is really hard.

Mathematics is a very difficult subject for many students, and many students have never passed the exam as soon as they enter high school, and even after graduating from college, they often have nightmares and dream about their math exams. It can be said that it affects a lifetime, so what is the difficulty of high school mathematics? Today we are going to analyze it:

1.Difficulty of comprehension of knowledge.

The first thing is the difficulty of understanding high school math knowledge, which seems to be understood on the surface, but I can't do anything when I do a problem. This is because when you first learn, you can't do in-depth understanding, and the level of understanding exists on the surface; After a certain amount of practice, the level of understanding will be different, and after the first round of review in the third year of high school, it is another realm; Of course, not every student will deepen their understanding layer by layer, and it is possible that they will not be able to understand it all the time, so they will not understand it at all, but they will only master some methods of solving problems, but they will not be able to change the question type. There are a lot of difficult knowledge to understand in high school, which makes it difficult for many students.

2.Problem solving is too skill-oriented.

If you want to say how advanced high school math is, it is definitely not as good as college, but high school math problems can be varied, although the knowledge points are limited, but the question type can be changed again and again. Among these changing topics, many of them are particularly technical, and many students can't even think of it, and they can't do it without a lot of training. These skills are very flexible and changeable, and there are many crossovers between knowledge points, and it is possible to test a function in a question, and finally find that it is solid geometry.

These tricks really stumped a lot of people.

How to break through?

The first thing must be to understand, understand the knowledge points, and think more; In addition, there is a lot of training, for the typical question types can be remembered, a lot of training can definitely be done practice makes perfect; Finally, pay attention to the induction, for the type of questions with particularly strong skills, blindly brushing the questions must not be of much effect, at this time, you need to summarize and analyze, and summarize some skills by yourself; It should also be emphasized that the study of high school mathematics requires students to persevere, persist and persist, learning is not an overnight thing, and time is indispensable if you want to learn well.

There is a class of x people and a second class of y people.

5/12x+y）×3/5=3/4x

1/4x+3/5y=3/4x

1/2x=3/5y

x/y=6/5

The number of students in a class is 6 11 of the whole grade

If there is a person in class 1 and a person in class 2, and five-twelves of the number of people in class 1 is transferred to class 2, the number of people in class 2 is (5 12)a+b, and the number of people in class 1 is (7 12)a, then [(5 12)a+b] (7 12)a=3 4, and the solution is b a=5 16, then a (a+b)=16 21

There may be an error in the calculation, and the process is such a ......

Let's assume that the original class size is xThe second class is y, and an equation is listed as follows.

3 5) (5x 12+y) = (3 4) (7x 12), and then find x (x+y) = 16 21