Requirements: 1. Write the process clearly. 2. The equation calculation should be with questions. 3. Except for the calculation equation, the idea of the questions should be written. (method) (1) 2X minus one third (x + 1) = 2x minus one half (2) A, B and 60, a is two-thirds of B, seek a, B (3) 24.8x37.5 divided by nine quarters (4) Three consecutive even numbers and 66, the ratio of these three numbers (5) After a 50% increase in the price of a piece of clothing, it was sold at a 20% discount, earning 200 yuan, seeking the cost The following six questions will be given extra marks if they are answered correctly by tomorrow morning I will hand in my homework tomorrow morning If you answer the above five questions correctly, you will get extra points Time doesn't wait!

1. 2X - (x + 1) / 3 = 2x-1 / 22x-x / 3-1 / 3 = 2x-1 / 2-x / 3 = - 1 / 2 + 1 / 3-x / 3 = - 1 / 6x = 1 / 22, a = 2 / 3, B, so a + B = 2 / 3, B + B = 60, B is equal to 36, a = 243, 24.8x37.5 divided by nine fourths = 1240 / 3 is 413 and one third 4

The purchase price of a certain commodity is 2880 yuan. When it is sold at a 20% discount on the marked price for the first time, due to poor sales, it is 10% discount for the second time, and the profit margin is 10%. Then, how much is the original marked price of the commodity and the profit margin of the original commodity?

Suppose the original price of the goods is x yuan
（x×80％×90％－2880）／2880＝10％
Solution: x = 4400 (yuan)
The profit margin of the original commodity is (4400-2880) △ 2880 × 100% = 52.78%
A: the original price was 4400 yuan, and the profit margin was 52.78%?

It is known that the polynomial (m-2) x ^ 5-x ^ (n + 1) + 4x + n about X is a quartic trinomial. Find the value of (m-n) ^ n

(m-2) x ^ 5-x ^ (n + 1) + 4x + n is a quartic trinomial
So the first item must be 0
M-2=0,M=2
The second index is 4
N+1=4,N=3
The result is the third power of - 1, which is - 1

Use the equation to solve: there are two kinds of alcohol with 75% and 45% concentration. To prepare 300 grams of alcohol with 65% alcohol, how many of these two kinds of alcohol should be taken?

Ask the mathematician, Hello! Set the concentration of 75% to take x g, the concentration of 45% to take 300-x g, 75% x + 45% × (300-x) = 300 × 65% 75% x + 135-45% x = 19530% x = 195-13530% x = 60x = 60 △ 30% x = 200g, the concentration of 45% to take 300-x = 100g A: the concentration of 75% to take 200g, the concentration of 45% to take 100g

7 out of 9 and 5 out of 6

7/9=7*2/9*2=14/18
5/6=5*3/6*3=15/18

The simple methods of seven eleven times four thirteen and nine eleven times seven thirteen

Hello: seven out of eleven times four out of thirteen and nine out of eleven times seven out of thirteen = 4 / 11x7 / 13 + 9 / 11x7 / 13 = 7 / 13X (4 / 11 + 9 / 11) = 7 / 13x13 / 11 = 7 / 11. If you don't understand this question, please click "adopt as satisfactory answer" if you are satisfied. If you have any other questions, please accept this question and send another one

Calculation: [- 20.5] + 2 and 1 / 4 + [- 3.5] + 3 / 4

[- 20.5] + 2 and 1 / 4 + [- 3.5] + 3 / 4
=[- 20.5-3.5]] + (2 and 1 / 4 + 3 / 4)
=-24+3
=-21

Use five nines to form the formula, make the result equal to 10, and write at least two formulas
As soon as possible, ask again ~ 1 / 12 is equal to how many parts plus how many parts

1 / 12 = 1 / 24 + 1 / 24!
9*9/9+9/9=10
9+9*9/9/9=10
9+9-9+9/9=10

-Mixed operation of 0.5 - (- two and a quarter) + 3.75 - (+ five and a half) simple rational numbers
One more question, 16 - seven and a half - (three and a third) - eleven and a half

-0.5 - (- two and a quarter) + 3.75 - (+ five and a half)
=（-0.5-5.5）+（2.25+3.75）
=-6+6
=0
16 - seven and a half - (three and a third) - eleven and a sixth
=8 and 1 / 2-3 and 1 / 3-11 and 5 / 6
=5 and 1 / 6-11 and 5 / 6
=-6 and 2 / 3
If you don't understand this question, you can ask,
In addition, please send and click my avatar to ask me for help,

6.868 * (- 5) + 68.68 * (- 1.2) + 686.8 * (+ 0.17)

6.868*(-5)+68.68*（-1.2）+686.8*（+0.17）=6.868*【(-5)+（-1.2）+（+0.17）】
=-6.868*6.03
=-41.41404