Junior one math problem, urgent, then add 20 points! In April 2009, our city opened the "Shaoyang Shanghai" through train, which provided convenience for the residents of our city to travel and commercial transportation. It is understood that after the opening of the through train, our city's tourism company added 400 yuan to the price of "Shaoyang Shanghai" line (unit: yuan / person), 5 / 6 of the price before the opening of Jiangwei through train, and 13 yuan to the cost of Shanghai tourism, It's equivalent to the cost of four people traveling to Shanghai after the opening of the through train. Try to find out the quotation of our city's tourism company for the "Shaoyang Shanghai" line before and after the opening of the through train

Junior one math problem, urgent, then add 20 points! In April 2009, our city opened the "Shaoyang Shanghai" through train, which provided convenience for the residents of our city to travel and commercial transportation. It is understood that after the opening of the through train, our city's tourism company added 400 yuan to the price of "Shaoyang Shanghai" line (unit: yuan / person), 5 / 6 of the price before the opening of Jiangwei through train, and 13 yuan to the cost of Shanghai tourism, It's equivalent to the cost of four people traveling to Shanghai after the opening of the through train. Try to find out the quotation of our city's tourism company for the "Shaoyang Shanghai" line before and after the opening of the through train

After the opening of through train, the quoted price of Shaoyang Shanghai line is X
3X+400=5/6*4X
18X+2400=20X
2X=2400
X=1200
So x / (5 / 6) = 1200 * 5 / 6 = 1000 yuan
A: before the opening of the through train, the quoted price of Shaoyang Shanghai line is 1000 yuan, and after the opening, it is 1200 yuan

Simplify (X-Y) ^ 3 times (Y-X) ^ 2 to
A（x-y）^5 B（x-y）^6 C（y-x）^5 D（y-x）^6

(X-Y) ^ 3 times (Y-X) ^ 2
=(x-y)^3*(x-y)^2
=(x-y)^(3+2)
=(x-y)^5
A

Junior one math problems, master into, help to solve within 5 minutes ah!
1. The mathematician Gauss once studied such a problem when he was in school, 1 + 2 + 3 + 4 +. + 10 =? After research, the general conclusion of this problem is 1 + 2 + 34 +. + n = 1 / 2n (n + 1), where n is a positive integer. Now let's study a similar problem: 1 × 2 + 2 × 3 +. + n (n + 1) =? Observe the following three special equations: 1 × 2 = 1 / 3 (1 × 2 × 3-0 × 1 × 2)
2×3=1/3（2×3×4-1×2×3)
3 × 4 = 1 / 3 (3 × 4 × 5-2 × 3 × 4) add these three lamp like sides to get 1 × 2 + 2 × 3 + 3 × 4 = 1 / 3 × 3 × 4 × 5 = 20. After reading this passage, please calculate: (1) 1 × 2 + 2 × 3 +. + 100 × 101 (just write the result) (2) 1 × 2 + 2 × 3 +. + n (n + 1) (write the calculation process) (3) 1 × 2 × 3 + 2 × 3 × 4 +. + n (n + 1) (n + 2) (just write the result)
2. This is a famous story. Archimedes played chess with the king, and the king lost. The king asked Archimedes what reward he wanted. Archimedes said to the king, "I just need to put one grain of rice on the chessboard first, two grains in the second, four grains in the third, sixteen grains in the fourth... And fill the whole chessboard in this way." the king thought that there was not much food left, (1) we know that there are 64 squares in chess, so how many meters should be put in the 64th square? (expressed by power) (2) please explore the number at the end of the number in (1). (briefly write the process of exploration)
(3) Ask the king how many grains of rice he lost to Archimedes
3. Where is the approximate number of 5000?

1. The answer is n * (n + 1) * (n + 2) / 3, which is analyzed as follows: = 1 / 3 * [1 * 2 * 3-0 * 1 * 2 + 2 * 3 * 3 * 4-1 * 2 * 3 + 3 * 4 * 5-2 * 3 * 4 +... + (n-1) * n * (n + 1) - (n-2) * (n-1) * (n + 1) * (n + 2) - (n-1) * (n + 1)] = n * (n + 1) * (n + 2) / 32

How to pronounce standard English words
I find that there is a gap between reading phonetic symbols and real people's pronunciation. What can I do to read standard (except listening to tapes)

First of all, learn the phonetic alphabet, what letter and letter combination often pronounce what sound, sentence beginning, middle, end, pronunciation are also different, this depends on the usual accumulation, of course, there are some special circumstances, but if you learn the phonetic alphabet well, most of them can be read out~

Grade 5 Volume 2 composition with 400 words
There should be a natural section!

There is an open space in front of the building. This open space is really a good place for football games. After school, the children come here again. They divide into two groups, pile up their bags and hats to make goals, and then they open the formation to play. The little brother and little sister are attracted, and the big uncle who passes by also sits on the sideline to enjoy their game

If ∠ A and ∠ B of △ ABC are acute angles, CD is high and AD / DB = (AC / BC) ^ 2 is known, what triangle is △ ABC? Try to prove
If ∠ A and ∠ B of △ ABC are acute angles, CD is high and AD / DB = (AC / BC) ^ 2 is known, what triangle is △ ABC?
The answer is "isosceles triangle or right triangle". Who can help me prove it, that is, how can I get the answer?

Let AD / DB = (AC / BC) ^ 2 = K
(AC/BC)^2=(CD^2+AD^2)/(CD^2+BD^2)
=(CD^2+k^2AD^2)/(CD^2+BD^2)=k
k*CD^2+k*BD^2=CD^2+k^2BD^2
(k-1)CD^2=k(k-1)BD^2
That is, AC = BC
Or CD ^ 2 = KBD ^ 2 = ad * BD, that is CD: ad = BD: CD ⊥ CD ⊥ ab
The Δ ADC is similar to the Δ CDB
∠A= ∠DCB ∠B= ∠ACD
∠C= ∠DCB +∠ACD =∠A+∠B= 90

mr and mrs green come from sydney.they have two children,jim and kate. they live in shanghai now.mr

The greens are from Sydney. They have two children, Jim and Kate. Now they live in Shanghai

All right, there are points
3 ^ (x + 1) times 2 ^ x-3 ^ x times 2 ^ (x + 1) equals 2 ^ 2 times 3 ^ 2
(I can't read it clearly: the X + 1 power of 3 multiplied by the x power of 2 minus the x power of 3 multiplied by the X + 1 power of 2 equals the 2 power of 2 multiplied by the 2 power of 3)
Ask how much x is. Don't just give the answer. If you have any questions, I'll add them
Good score

3 ^ (x + 1) times 2 ^ x-3 ^ x times 2 ^ (x + 1) equals 2 ^ 2 times 3 ^ 2
It can be reduced to (3 ^ x) * (2 ^ x) (3-2) = 6 ^ 2
Then it is reduced to 6 ^ x = 6 ^ 2
So x = 2

How to calculate the area of a right triangle?

From the data, we know that this is an equilateral right triangle. Such two equilateral right triangles can be combined into a square. Square area = side length multiplied by side length, so equilateral right triangle area = side length multiplied by side length and then divided by 2

Is the subject an article predicate and the verb a third person singular?

When the subject is a countable noun in the plural, the predicate is also in the plural
The third person singular is used when the subject is an uncountable noun
Sometimes a + singular countable noun is used to denote a class