Please help me come up with a math paper in the order of the following questions! Come on! 20 bounty

1. Analysis: A year ago, Lao Zhang bought at least x breeding rabbits, x+2 2 3*(2x-1) solution x 8, x-1 0, and x z

x 1 2, and x z

When x is a non-positive integer, 2x-1 represents a negative odd number.

3 Analysis: Let three consecutive positive integers be x, x+1, x+2, x+x+1+x+2 333, and we get x 110

The maximum group is 109,110,111,4, and the analysis of this class can ensure that it is not eliminated before the play-offs.

Because the winners and losers are relative and come in pairs. You can analyze the table and analyze the 4 class single round-robin, with a total of 6 games.

Not necessarily qualifying.

b: x as long as it is zero or a negative integer. Such as 0, -1, -2 ,..

A: At least 11 of them.

b: x is less than or equal to 0, and x is an integer.

C: There are a total of 109 groups, the largest being 109, 110, 111D: first, to ensure that they are not eliminated before the play-offs. Second, it may not be able to qualify.

The above is a personal opinion only.

The earliest to put forward and describe this mathematical problem was the topic of "things do not know the number" in the mathematical work "Sun Tzu's Arithmetic" during the Northern and Southern Dynasties. The title of this "things don't know how to count" goes like this:

There are some things that are not known in number. If you count it in threes, there are two left; If five of five are counted on the ground, there are three left at the end; If seven and seven are counted in the ground, there will be two left. Q: How many of these things are there? ”

Not as you understand it. In fact, 70 is divisible by 5 and 7 but divided by 3, 1 by 21, divisible by 3 and 7, but divisible by 5 by 1, 15 divisible by 3 and 5 but divided by 7 by 1. In the problem, this number is divided by 3 by 2, then 70 is multiplied by 2, 5 is divided by 3, then 21 times 3, 7 divided by 2, then 15 times 2, and add.

Depending on the situation, minus the multiples of the least common multiple. Subtract 105 by 2 times to get 23.

This system algorithm was obtained after the study of Qin Jiushao, a mathematician in the Southern Song Dynasty.

This is known as the Chinese remainder theorem.

23 The common multiple of three and seven plus two.

It's also an ancient text.,,I don't understand what the ancient text means.,Hehe.。

It's a simple question.

Solution: By (2x-y) (x+y)=2 3

Then 2(x+y) = 3(2x-y).

i.e. 2x+2y=6x-3y

Sorting out the moving items yields 4x=5y

The solution is x:y=5:4

Hehe, I hope it helps.

Don't be afraid of ratio-type problems: In general, you don't find a solution directly, but you can get a proportional relationship between the two.

The ratio of (2x-y) to (x+y) is two-thirds.

i.e. (2x-y) (x+y)=3 2

Simplification yields x=5y

Then x:y=5:1

3(2x-y)=2(x+y)

6x-3y=2x+2y

4x=5yx:y=5:4

Thank you, hope it helps

The first column is the fraction (2x-y):(x+y)=2:3, the cross multiplication, the two sides are still equal, 3(2x-y)=2(x+y), and the coefficient is multiplied into 6x-3y=2x+2y

xy moves to each side of the equation 4x=5y

Dividing by 4y is still equal x:y=5:4

Let 2x-y=2a; x+y=3a

The solution is x=5 3a

y=4/3a

So x:y=(5 3a):(4 3a).

5 4 is five out of four.

Let x = ay, and bring in the original form, i.e.

2ay-y)/(ay+y )

2a-1)/(a+1)

The solution gives a=5, i.e., x=5y, so x:y=5

The ratio of (2x-y) to (x+y) is two-thirds.

2(2x-y)=3(x+y).

That is, 4x-2y=3x+3y

i.e. x=5y, so.

x：y=（5：1 ）=5

(1) a (5 6) b (2 9), reduced to 15a 4b, then a:b 4:15.

2) allocate 1/6 of the number of people in Group A to Group B, treat the original Group A as 6 shares, take out 1 share and leave 5 shares; And Group B plus this is also 5 copies, so Group B should have 4 copies. （6－4）÷4＝1/2。

3) The number of ducks is 560 (1 1 4) 448, and the number of ducks is 560 448 112 fewer than that of chickens.

4) The remaining 4 7 of the repaired 2 5, which is enlarged twice (5 2) on both sides at the same time, is still equal, 2 5 5 2 1, 4 7 5 2 10 7, i.e. the remaining 10 7 of the repaired (all);

If you look at the rest as the unit "1", then the rest is 6800 (1 10 7) 2800 meters.

5) Set up workshop B to donate x yuan, and the donation of workshop A is 1 2 of the donations of the other two workshops, that is, the donation of workshop A.

x＋2000）× 1/2＝1/2 x＋1000

The donation of workshop B is 1 3 of the contribution of the other two workshops, that is, the donation of workshop B.

1 2 x 1000) 2000 1 3 1 6 x 1000, because workshop B donated x yuan, so.

1/6 x＋1000＝x

5/6 x＝1000

x＝1200

Because the donation of workshop A is 1 2 of the donations of the other two workshops, the donation of workshop A.

1200 2000) 1 2 1600 yuan.

6) 1 9 of the total number of sold in the first week, then the remaining 1 1 9 8 9;

Sell the remaining 3 8 in the second week, then you have 8 9 (1 3 8) 8 9 5 8 5 9.

Today's students are really, not only poor in academic performance, but also in poor moral character! It is harder to ask him to take a few seconds to adopt it than to ask someone to spend hours doing 10 questions! It's really a declining world and a moral decline!

<> please ask the wax liquid to pick the wheel and tell the ants.

<> Sakura Sun Douzhi grinds Kai and yo.

Cosine theorem, solve the equation yourself.