In the first year of junior high school, there is a reward for a high score

Set up Beijing to Chongqing, transport X, transport 10-x to Wuhan, Shanghai to Chongqing, transport 8-x, Shanghai to Wuhan.

4-[8-x] set.

Therefore, the freight cost of goods from Beijing to Chongqing is 800x the freight of materials from Chongqing to Wuhan.

400【10-x】

The shipping fee from Shanghai to Chongqing is 500 [8-x] The shipping fee from Shanghai to Wuhan is.

300｛4-【8-x】｝

And because the total shipping cost is 7,600 yuan, the answer comes out.

Join up 800x+400【10-x】+500【8-x】+300{4-[8-x]} 7600

Solution x 4 so Beijing to Chongqing 4 units to Wuhan 10-4 6 units.

Shanghai to Chongqing 8-4 4 to Wuhan 0.

Above, do you see the title clearly?? One yuan equation, some of you are still 3 yuan halo.

Beijing transferred to Wuhan X station, then transferred to Chongqing 10-X station; Then Shanghai was transferred to Wuhan 6-x units, and Chongqing 8-(10-x)=x-2 units.

400x+800（10-x）+300（6-x）+500（x-2）=7600

Solution, x=6, then 10-x=4, 6-x=0, x-2=4, so Beijing transferred 6 units to Wuhan and 4 units to Chongqing; Shanghai was transferred to Wuhan for 0 units and Chongqing for 4 units.

Set: X station from Beijing to Chongqing, 800x+400(10-x)+500(8-x)+300[6-(10-x)]=7600

Beijing gave Chongqing 4 units to Wuhan 10-4 = 6 units, Shanghai gave Chongqing 4 units.

Solution: Beijing will be transferred to Wuhan Station A, Chongqing Station B, Shanghai will be transferred to Wuhan Station C, and Chongqing Station D will be transferred. The total shipping cost is Z.

z=400a+800b+300c+500d=7600a+b=10

c+d=4b+d=8

a+c=6 solution: a=6 b=4 c=0 d=4 so Beijing transferred 6 to Wuhan, 4 Chongqing, 0 Chongqing to Wuhan, 4 Chongqing.

1.If -(a-7) is negative, then a-7 02Simplify.

3.On the array, if the points a and b represent two numbers that are opposite to each other, and the distance between these two points is , then the distance between these two points is and .

3.Find a pattern to fill in the numbers.

1 1 1 2 -1 3 1 4 , -1 5 , 1 6 The 2008th number is 1 2008

Use for solid and use for hollow. There are a number of solid and hollow cores, which are arranged according to certain prescribed rules as shown in the figure below. ：☆

Q: How many hollows were there in the first 2009? 223*3+1=670

1993 1993 multiplied by the result, the last digit is 3

The last digit of 1997 is 7

3 to the nth power, the result is 3, 9, 27, 81 ,......Press the last digit as 3,9,7,1,3,9,7,1....Circulate.

1993 divided by 4, the remainder is 1, so it should be 3,9,7,1 to the nth power of the first ———37, the result is 7,49,343,2401, and the last digit is 7,9,3,1,7,9,3,1....Circulate.

1997 divided by 4, the remainder is 1, so it should be 7,9,3,1 the first ——— 7 Happy learning!

The first multiplication of 1993*1993 mantissa is 9

The second multiplication is 199 3*1993*1993=27 The mantissa is 7, and the third multiplication is 1993*1993*1993*1993=81 The digit is 1, and the fourth multiplication is the same as above, and the mantissa is 3

Note: Just multiply by their single digits.

With the above rule, it can be concluded that they multiply the mantissa number as 3, 9, 7, 1, four cycles, then 1993 is divided by four cycles and the remaining 1, and the mantissa is 3.

The multiplication of 1997 and 1997 is also the first way to calculate the law of multiplying the mantissa in the calculation of the remainder of 1997 is the first number of numbers.

The answer is 9 because the last digit of 1993*1993 is 3, 3*3=9

The last digit of 1997*1997 is 7, 7*7=49

That's it. It's all 9

You only need to pay attention to the end, 1993 1993 multiplication is actually to pay attention to the last 3 multiplication, 2 1993 multiplication end is 9, then multiply by 1 1993 end to 7, then multiply by 1 1993, the end is 1, and then multiply by 1 1993 end for 3, this is a round of cycle, that is, 4 1993 multiply for a round of cycle, the end of 4 is based on this, multiply to the end of the fifth 1993 and return to 3, so 1993 is left with 4 results in 1, Thus the end is the first of a cycle: the 1997 multiplication principle is still the same, and the result is 7.

1.The last digits are all multiplied by 3: 3*3=9 3*3*3=27 3*3*3*3=81 3*3*3*3*3=243 3*3*3*3*3*3=739 .

By analogy, multiplying four 3s begins to repeat, 1993 4 = 498 remainder 1 so the final end number is 3

2.The method is the same as above: the result is four to cycle, 1997 7 = 285 and 2 remainder so the result is 9

The first one is 1 and the second one is 3

1993*1993*1993*1993*1993--- the single digit is 3,--1).

So it can be simplified to 398 3s multiplied and then multiplied by 1993*1993*1993.

It is then simplified to 402 3s multiplied, and then simplified to 80 + 2 3s according to (1), and finally simplified to 3*3*3*3, with the last number being 1

1993 1993 multiplied by the result, the last digit is 3

The last digit of 1997 is 7

3 to the nth power, the last digit is 3, 9, 7, 1, 3, 9, 7, 1....Circulate.

1993 divided by 4, the remainder is 1

7 to the nth power, the last digit is 7, 9, 3, 1, 7, 9, 3, 1....Circulate.

1997 divided by 4, the remainder is 1

Multiply the numbers at the end of two numbers and take the last number.

You can list the vertical ones and you'll see why.

The first 9, because 3 3 = 9

The second 9 because 7 7 = 49

1.If the product of the only number of two rational books is 0, then the two liquid numbers (at least one of which is 0) 2Columnar calculations.

1-3+5-7+9-11……Posture +97-993If x+3 + y-1 = 0, then 4/y=(1)x+3 + y-1 =0

x=-3 y=1

4/x-y = -1

1、a(1-3)+(5-7)+(9-11)……Tuanchai cover Qiao + (97-99) 3, from the collapse type x+3=0 to obtain x=-3; is obtained by y-1=0, y=1

is equal to -1

Solution: Let the distance be x kilometers.

x/100+x/80+1/2=5

9x/400=9/2

x=200A: The distance is 200 kilometers.

Let the distance be x

x/80 ＋ x／100 ＋0·5=5x=200

The distance is two hundred

Find the average speed of the round trip (100+80) 2=9090*

Hello, glad to help you solve the problem.

1.A{x+y=(20) 12x+8y=(180) B: {x+y=(180) x 12+y 8=(20).

A: x represents the number of days of remediation of a, y represents the number of days of remediation of b, b: x represents the number of meters of remediation of a, y represents the number of meters of b remediation 2(You can use either A and B above).

1) (a) Set a remediation x days b remediation y y days.

x+y=20 12x+8y=180

Solution: x=5 y=15

2) (B) Set a remediation x m b remediation y m.

x+y=180 x 12+y8=20 The solution is: x=5 y=15

Answer: A remediates the river for 5 days, and B remediates the river for 15 days.

I don't know how to ask again. Hope it helps.

People from all walks of life are welcome to give advice and criticism.

1.A{x+y=(20) 12x+8y=(180) B: {x+y=(180) x 12+y 8=(20).

According to the equations of students A and B, please point out the meaning of the unknown numbers x and y respectively, and then complete the equations listed in A and B in parentheses.

A: x means the number of days A has done the project y y: The number of days B has done the project.

B: x represents the number of rivers that A has done for this project and y has been the number of rivers that B has done for this project.

2.Ask the two engineering teams to remediate the river channel for how many meters.

According to the equation 2x+y=180

x/12+y/8=20

The solution is x=60 and y=120

The number of rivers that A remediates for this project is 60 meters, and the number of rivers that B remediates for this project is 120 meters.

A said: the number of working days of the two engineering teams; B: The length of remediation of the two teams;

A: 60 meters, B, 120 meters.

1) Set the distance to x

then x 5 - x 7 = 10

x=1752) without equations. It takes 175 (5+7) time to meet, multiplied by Kai's speed. 5*175 (5+7)3) can also be used without equations, if used, you can set x seconds after mouthing.

At this time, the two of them ran the same distance. then 7*x=5*(5+x). The solution is x=

Use the volume formula of the ball to find the volume of the ball: 4/3 x x cube of radius = 4 3*3*4000 cube = 256 times 10 to the ninth power (cubic kilometers) = 256*10 to the ninth power * 10 to the 15th cubic centimeter = 256*10 to the 24th cubic centimeter.

8000 cubic centimeters: 256*10 to the 24th power cubic centimeter = 1 (32*10 to the 21st power) and then multiply this number by the 34th power of 10 to get 10 to the 13th power 32, which is definitely larger than 530. Dividing it by 530 is how many times larger.

Take 3 words.

Super Diamond Star Volume = (4 3) (2000) Cubic Kilometers = 32 10 9 Cubic Kilometers = 32 10 18 cubic meters = 32 10 27 cubic centimeters.

The weight of 8000 cubic centimeters is 10 34 (32 10 27) 8000 = 8000 32 10 7 = 250 10 7 = 100 million carats.

4.71 million times.

3x +5 y = k +2（1）

2x +3 y = k（2）

4x +6 y-3x-5y = 2k-k-2x + y = k-2

Meet x + y = 2

k-2 = 2

k = 4.

The second question is wrong!

2x-3y = 3, 3 x +2 y = 11x = 3, y = 1.

3a + b = 1，a-3b = 3

So = 3 5 = -4 5

This is the first year of high school.

I'm also in my second year of junior high school.