For a math problem, I will add 40 points, very urgent!

Because 3a-b-7>=0, 2a+b>=0

And because the root number (in the root number: 2a+b-3) = 0

So 3a-b-7 = 0, 2a + b-3 = 0

So a=2, b=-1

i.e. (b+a) a=(2-1) 2=1

Because 3a-b-7>=0, 2a+b>=0

And because of this, 3a-b-7=0, 2a+b-3=0

So a=2, b=-1

i.e. (b+a)(b+a)=(2-1) 2=1

Because it is greater than or equal to 0; The root number (2a+b-3) is greater than or equal to 0.

Root number (2a+b-3) = 0

a=2 b=-1（-1+2)^2=1

Root number (2a+b-3) = 0

3a-b-7=0

2a+b-3=0

a=2 b=-1

a+b)^a=1^2=2

So the result is equal to the square root of 2.

The solution is as follows: 3a-b-7=0

2a+b-3=0

The solution yields a=2, b=-1

So the final answer is 1

1.Solution: The journey of three people is 6:12:18=1:2:3, so A: 36x1 6=6 yuan.

B: 36x2 6=12

C: 36x3 6=18 yuan.

2.Solution: According to the title, there is.

A + B + C + D = 128

Since A+3=B-3=C3=D*3, then.

A = D * 3-3, B = D * 3 + 3, C = D * 9 so there is D * 3-3 + D * 3 + 3 + D * 9 + D = 128 solution Ding = 128 16 = 8

So A = 8 * 3 - 3 = 21

B = 8 * 3 + 3 = 27

C = 8 * 9 = 72

12 of the same pumping machines are required for the end of the day.

How many days is 5 pumps for 20 days, which is equivalent to 1 pump? 5 20 = 1006 units pumping for 15 days, which is equivalent to 1 pumping for how many days? 6 15 = 90 (20-15) days of water flowing into the reservoir equivalent to 1 pump, how many days? 100-90=10

How many days does 1 pump of water flowing into the reservoir in 1 day? 10 How many days does the original water in the 5=2 reservoir be equivalent to 1 pump? 100-2 20=60 or 90-2 15=60

How many days is 6 days of water flowing into the reservoir equivalent to 1 pump? 2 How many pumps do I need to pump in 6=126 days? （60+12）÷6=124.The user spends a total of 12 months on the electricity bill (yuan, and the modification fee is 100 yuan.

The electricity consumption before the modification is yuan, so a total of 1272-1008-100 164 yuan is saved.

Hello! 1.Solution: There are many ways to do this, but the more reasonable ones are:

The first 6 kilometers are divided equally among three people, 6 12 B C are evenly shared, and the last 6 kilometers are paid by C.

Equation: 36 18 2 (yuan).

2 6 2 4 (yuan).

4 (12 6) 2 2 10 (RMB).

10 (18 12) 2 22 (RMB).

A: A pays $4, B pays $10, and C pays $22.

This question cannot be calculated by distance).

2.Solution: According to the title, there is.

A + B + C + D = 128

Since A+3=B-3=C3=D*3, then.

A = D * 3-3, B = D * 3 + 3, C = D * 9 so there is D * 3-3 + D * 3 + 3 + D * 9 + D = 128 solution Ding = 128 16 = 8

So A = 8 * 3 - 3 = 21

B = 8 * 3 + 3 = 27

C = 8 * 9 = 72

12 of the same pumping machines are required for the end of the day.

How many days is 5 pumps for 20 days, which is equivalent to 1 pump? 5 20 = 1006 units pumping for 15 days, which is equivalent to 1 pumping for how many days? 6 15 = 90 (20-15) days of water flowing into the reservoir equivalent to 1 pump, how many days? 100-90=10

How many days does 1 pump of water flowing into the reservoir in 1 day? 10 How many days does the original water in the 5=2 reservoir be equivalent to 1 pump? 100-2 20=60 or 90-2 15=60

How many days is 6 days of water flowing into the reservoir equivalent to 1 pump? 2 How many pumps do I need to pump in 6=126 days? （60+12）÷6=124.Set any number to indicate the electricity consumption a (kWh).

Peak and valley electricity: >

So don't use peaks and valleys to save money.

Is there anything else you can ask me again?

I wish the landlord unlimited money and everything!

1. Since three people sat together for 6 + 12 + 18 kilometers, which is equivalent to a total of 36 kilometers, the cost per kilometer per person is: 36 yuan 36 kilometers = 1 yuan kilometer, and the payment is 6 yuan, 12 yuan, and 18 yuan.

2. Let the score be: A, B, C, D, then there is A + B + C + D = 128, where 3 D = C 3 = B - 3 = A + 3

Know: D = A 3 + 1, C = 3 A + 9, B = A + 6, know: A + A + 6 + 3 A + 9 + A 3 + 1 = 128

A = 21, B = 27, C = 72, D = 8

3. Let the inventory be z, the daily water intake is y, and the pumping water of each pump per day is x, then there is 5x*20=20y+z(1); 6x*15=15y+z（2）；There is (1)-(2) formula, 5y=10x, know y=2x, thus know z=60x, if m machines are needed to drain, then there is 6mx=6y+z, and m=(6y+z) 6x=12 (sets) are obtained

4. The original fee is: 200 (degree month) * 12 (month) * yuan degree) = 1272 yuan.

After the new meter is adopted, the cost is: 100 (degree month) * 12 (month) * yuan) + 100 (degree month) * 12 (month) * yuan) + 100 yuan = 1108 yuan, that is, you know that you can save 1272-1108 = 164 yuan.

1.Solution: The journey of three people is 6:12:18=1:2:3, so A: 36x1 6=6 yuan.

B: 36x2 6=12

C: 36x3 6=18 yuan.

1 5 = 1/5 1 4 = 1/4 1-1/5 - 1/5 = 1/20 5 4=

1/20 =

A: There was a power outage for 1 hour.

The power outage time is x hours:

1-x/5=

x = 2 (hours).

1.The base area is 72 square centimeters, the bottom circumference is 34 cm, the bottom rectangle is 9 cm long, 8 cm wide and 6 cm high.

The surface area of this cuboid is 2*(9*8+9*6+8*6)=348 square centimeters.

Yang should prepare at least square meters of tiles.

There are 3 different spellings.

1.A cuboid with a base area of 72 square centimeters, a base circumference of 34 centimeters and a height of 6 centimeters. What is the surface area of this cuboid in square meters?

34 6 + 72 2 = 348 (square centimeters).

2.Sunshine community to replace the swimming pool tiles, has been the swimming pool 25 meters long, 18 meters wide, high meters, at least how many square meters of tiles to prepare?

25 18+25 sq.m.).

How many different ways are there to assemble a small cube with an edge length of 1 cm into a large cuboid?

1 1 12 2 1 6 3 4 1 2 2 3 A total of 4 spellings.

1.Let the length be x and the width be y, then 2(x+y)=34, xy=72, so x=9, y=8

Therefore, the surface area of the cuboid is: 2(8 9 + 6 9 + 6 8) = 3482The area of the tiles is the side area of the swimming pool + one bottom area = 2 (25

3.Three kinds. The first type is 12 in length, 1 in width, and 1 in height

The second type is 6 in length, 2 in width, and 1 in height

The third type is 4 in length, 3 in width, and 1 in height

The fourth type is 3 in length, 2 in width, and 2 in height

1.Let the length be a and the width be b

2a+2b=34

a×b=72

Get a=9, b=8

Surface area: 2 9 8 + 2 9 6 + 2 8 6 = 348 So the surface area of the cuboid is square meters.

So at least prepare square meters.

3.There are four kinds.

1.Let the length, width and height of the box be: xyz

x+y=17

z=6 solves x=8,y=9;Or x = 9, y = 8 so the surface area of the rectangle is: 348 square centimeters.

2.Area = Base Area + Side Area.

3.There are 8 different spellings.

According to the bottom surface, it can be divided into:

1, 2, 4, 6, 12 small cubes of the big cuboid have 1, 1, 1, 2, 2, 1 spellings.

So there are 8 ways to do it.

1) The length and width of the bottom are x, y x*y=72 x+y=17 x=9 y=8 Answer: 348 square centimeters 2) 25 * Calculate it yourself * is the meaning of multiplication.

1.Let the two sides of the bottom surface be a and b, then there is ab=72, a+b=34 2=17, so a=9, b=8. The surface area is up to you.

The small cubes at the bottom can be 12, 6 or 4, which can be represented as 1*12, 6*2, 4*3.

Upstairs 2 * 2 * 3, in fact, is 4 * 3, the spelling is the same, can only be regarded as a spelling.

*2+34*6 348 square centimeters square meters *18+25* square meters.

There are 1 length, 2 widths, and 6 heights

Length 1, width 3, height 4

Length 1, width 1, height 12

Length 2 width 3 height 2

Four spellings (length, width and height are interchangeable).

(1) Let the length x width of the ground be y xy=72 x+y=17, so x,y are 8 and 9

The surface area is 72*2+8*6*2+9*6*2=348(2)5 faces: 25*18+25*, I don't count: (3)1*1*12 1*2*6 1*3*4 2*2*3 4 types.

1.The side area of the box is 34*6=204

Total area = side area + 2 * bottom area = 204 + 2 * 72 = 3482The circumference is 2*(25+18)=86

Tile area = bottom area + side area = 25 * 18 + 86 * 3Four.

In a row: 12x1x1

Two columns: 6x2x1

Three columns: 4x3x1

Combo: 2x2x3

The first sub-problem is a pair of vertex angles, parallel to each other, with a set of angles, and a midpoint with a set of edges, congruent.

A parallelogram A group of opposite sides that are parallel and equal (congruent obtained).

1.If a 0 b, and the distance from the point of a to the origin on the number axis is greater than the distance from the point of b to the origin, try to arrange the four numbers a, -a, b, and -b in descending order.

a|>|b|

a>-b>0>b>-a

2.The following numbers are concatenated with signs: minus five-quarters, 1,,, minus sevenths, 0, and one-quarter three-quarters.

5 4<-7 5<<0<1<1 and 3 4<3Write out the points that are 3 units of length and units of length from the origin, and connect these numbers with a sign.

3 units from the origin length 3 ,-3

Unit length from the origin.

4.Write out all integers greater than -4 but not greater than 2.

1、a>-b>b>-a

2. Minus 5/4 "minus 5/7<< 0<1 "1 and 3/4< 3, > 3>-3 >

1.-a,b,-b,a

2.minus 5/4 minus 5/7 1 and 3/4 3These points are:,-3,3,4There are: -3, -2, -1, 0, 1, 2