A math problem, the first year of junior high school, speed speed kneeling and hurrying

Solution 1: Equation:

Setting: The original x bucket wine in the pot.

After meeting the shop and flowers, the wine in the pot is: 2x-1;

After the second encounter shop and flowers, the wine in the pot is: 2 (2x-1)-1;

After the three encounters and flowers, the wine in the pot is: 2[2(2x-1)-1]-1;

Therefore, there is a relation: 2[2(2x-1)-1]-1 0;

Solution: x=7 8;

Solution 2: Arithmetic:

After inverse reasoning, it is obtained:

The last flower drink before a bucket: 0+1=1;

In the end, the store is doubled, then the original: 1 2 = 1 2;

The second time I met the flower and drank a bucket, the original: 1 2 + 1 = 3 2;

The second encounter is doubled, then the original: 3 2 2 = 3 4;

The first time I met a flower and drank a bucket, original: 3 4 + 1 = 7 4;

The first time you meet the store, it is doubled, then the original: 7 4 2 = 7 8 comprehensive or more to get 7 8 buckets.

Three encounters with shops and flowers, drink up the wine in the pot", It can be seen that there is a wine bucket in the pot when the three encounters the flower, then there is a wine bar 1 2 buckets when the three encounters the shop, then, there is a wine 1 2 + 1 bucket when the second encounter flower, and there is a wine (1 2 + 1) 2 bucket when the second encounter shop, so there is wine (1 2 + 1) 2 + 1 bucket when the flower is encountered, and there is wine when there is a store when the store is encountered, that is, the calculation formula of the original wine in the pot is.

1 2+1) 2+1] 2=7 8 (bucket.

100*1/99 + 99*1/98 +.3*1/2 + 2*1/2?

100*1/99 + 99*1/98 +.3*1/2 + 2*1/1.

100*1/99 + 99*1/98 +.3 * 1/2 + 2 * 2/1 = 99 100

1 original = 1 99-1 100 + 1 98-1 99 + ......1/2+1

Is the second question missing a 7?

3rd order without x, a-1=0, a=1

Original = x to the power of 4 + 2x to the power of 2 - 3x + 3

x = -1, the 4th power of the original = -1 + 2 * (-1) to the 2nd power -3 * (-1) + 3

1.Let the length S1 = 4m, V1 = 110km HS2 = 12m, V2 = 100km car defeat H

16 seconds. 2.Suppose the cost of paving a tile is a, the cost of buying a tile is b, the cost of paving a wooden floor is c, and the cost of buying a wooden floor is d, then the closed biverver can be obtained according to the title:

a=c+5b=3/4*d

a+b=110

c+d=135

Solving the equation yields: a=20 b=90 c=15 d=120

Lenovo's has an X unit. Then the acer base has (42-x).

2800x+(42-x)*3200=125600x=22.

Lenovo has 22 units and Acer has 20 units.

Lenovo laptops and Acer laptops are each equipped with Y equations.

x+y=42

2800x+3200y=125600

Explain it yourself.