Who can solve this math problem? Rush Rush Hurry

Friend, I'm on a mission, hope!

Daddy's speed is brother's (100-20) 100=80%.

Therefore, the elder brother has to go backwards (1 80%-1)*100=25 meters to let them reach the finish line at the same time.

Daddy's speed is brother's (100-20) 100=80%.

1 80%-1)*100=25 Backward 25 meters.

Guo Ximei, a native of Meixian County, Shaanxi Province, and a member of the Communist Party, joined the army in July last year and worked as a worker in a factory for the families of the troops.

Her lover Zhang Xinkui applied to serve as an instructor in the second company of a certain department on the front line. She actively supported her husband to go to the front line and take care of her.

The children take care of the household chores of the elderly, and they do a good job. In March this year, Zhang Xinkui rescued his comrades in battle.

Honorable sacrifice.

Solution: When A has run 100 meters:

Daddy's speed is brother's (100-20) 100=80%.

1 80%-1)*100=25 Backward 25 meters.

100-meter race, when the elder brother finishes the road, Dad is still 20 meters away from the finish line, then at the same time, the brother's speed is 5 4 times that of Dad, and the next step is to make Dad reach 100, so my brother is 125, so my brother is 25 back

Let's say dad is four meters per second and brother is five meters per second. The duration is 20 seconds. It takes 25 seconds for Dad to run 100 meters, and my brother can run 125 meters in 25 seconds, so he goes back 25 meters.

You wrote that the formula of the imperial union is a formula for finding the root of a quadratic equation, and the original equation should be: (2m -1) x +2mx + 1 = 0, this equation is difficult for me to solve. But if you write it wrong, 2m-1 is 2m-1, then this equation is peeled:

2m-1)x +2mx+1=0, which can be multiplied with cross-phase traces. It becomes [(2m-1)x+1](x+1)=0, then x =-1, x =1 1-2m.

Simplify, simplify the root number by 4-4m

x=-m±√(1-m²)

1. Let A be x and B be y

Let's sort out the steps.

A B1 x y1/2x+y

2/3（1/2x+y）

2 3(1 2x+y)+1 4 1 2x+1 3(1 2x+y) In any case, the sum of their money is 2000 yuan.

Formulas can be obtained. x+y=2000

3/4〔1/2x+1/3（1/2x+y）〕-2/3（1/2x+y）+1/4〔1/2x+1/3（1/2x+y）〕｝=650

Simplified to x+y=2000

1/18x-17/36y=650

Then just figure it out.

There may be a mistake in the middle of the way, you can just do it according to this idea.

2. Set the number of students in one class as x and the number of students in class two as y

It can be listed as x+y=90

3/4x+5/6y=71

The solution is x=48 y=42

3/4x=3/4*48=36

5/6y=5/6*42=35

The first class of Young Pioneers accounted for 36 71 of all Young Pioneers

The Young Pioneers of the second class accounted for 35 71 of all the Young Pioneers

The number of Young Pioneers in the first class is higher than that in the second class

Answer: The number of Young Pioneers in the first class is 1 71 more than the number of Young Pioneers in the second class!! I.

Laborious.

It's a cuboid – 4 long, 3 wide, and 15 high

The hypotenuse is the hypotenuse of 3 and 4.

All flutes (3+4+15)x4=88

Surface area: (3x4 + 3x15 + 4x15) x2 = 234 volume: 3x4x15 = 180

It should be a cuboid. The length is 4, the width is 3, and the height is 15

From above, the hypotenuse is 5, which happens to prove to be a cuboid Pythagorean theorem.

Therefore, the surface area is 4x3x2+4x15x2+3x15x2 and the volume is 4x3x15

The sum of the edge lengths is (3+4+15)x4

1.There are 3600 left, indicating that this part is the remaining 60%, so the number of parts processed by C is = 3600 * 40% (1-40%) = 2400, and the number of parts remaining before processing C is 6000,; B processed, 6000*25% (1-25%)=2000, C B processed a total of 4400 parts.

2.Let the total number of pencils be x, then 1 7x+1 4x+2(1 4x-1 7x)+11=x, and calculate x=28, then A is 28*1 7=4

3.If the total length of the highway is x meters, then 1 8x+5+1 5x-14+63=x, and x=80 meters are calculated.

4.If there are x people in workshop A and (260-x) people in B, then (260-x+50)-(x-60)*50%=4, and x=224 is calculated

5.If the total length of the canal is x meters, then 30%x+30%x*8 9+30%x*8 9+75=x, and x=450 meters is calculated.

1.Solution: Workshop B made this batch of parts:

1-20%)25%=20%C workshop made this batch of parts: (1-20%-20%)40%=24%3600 (1-20%-20%-24%)=10000 (pieces) B: 10000*20%=2000 (pieces).

C: 10000*24%=2400 (pcs).

2.Solution: Set this batch of pencils with a total of x pieces.

x-1 7x-1 4x-2(1 4x-1 7x)=11 gives x=28

A: 28*1 7=4 (branches).

3.Solution: Let this road be x meters long.

x-(1 8x+5)-(1 5x-14)=63 gives x=80

4.Solution: The original X people in the armor workshop.

50%（x-60）+4=260-x+50

Solution x=224

5.Solution: The total length of this canal is x meters.

x-30%x-8 9*30%x-75=8 9*30%x, x=450

1.Solution: Workshop B:

1-20%)25%=20% C workshop: (1-20%-20%)40%=24%3600 (1-20%-20%-24%)=10000 (pieces) B: 10000*20%=2000 (pieces).

C: 10000*24%=2400 (pcs).

2.Solution: Set this batch of pencils with a total of x pieces.

x-1 7x-1 4x-2(1 4x-1 7x)=11 gives x=28

A: 28*1 7=4 (branches).

3.Solution: Let this road be x meters long.

x-(1 8x+5)-(1 5x-14)=63 gives x=80

4.Solution: The original X people in the armor workshop.

50%（x-60）+4=260-x+50

Solution x=224

5.Solution: The total length of this canal is x meters.

x-30%x-8 9*30%x-75=8 9*30%x, x=450

ad=3

Let OE be perpendicular to Ac, the perpendicular foot is E, which has OE = 2 root number 2, ob = 3, and get EB = 1, so there is AE = AB + EB = 4, in the triangle AOE, the hypotenuse ao is equal to 2 root number 6, and then in the triangle AOD, the solution is AD = root number 15, hehe, just now I saw 2 root number 2 as root number 2, so I miscalculated, and now the result is root number 15

2 + 5 2 = 9 2 kg is equivalent to 1-3 7 = 4 7 of this watermelon, this watermelon has a total of 9 2 (4 7) = 9 2 7 4 = 63 8 kg, and the younger brother ate 3 7 63 8 = 27 8 kg.

5 2 kg = 20 8 kg, 20 8 27 8 brother eats more.

Altogether: (2+5 2) (1-3 7)=kg) brother; kilograms).

kg 5-2 kg.

My brother eats a lot.

Sister: 2 kg.

Brother: 5 2 = kilograms.

Younger brother: (2+ more brothers.)

Total watermelon weight (2 + 5 2) (1-3 7) = 63 8 The younger brother eats (63 8) * (3 7) = 27 827 8 > 20 8 = 5 2

So the younger brother eats more.

Watermelon weight (2 + 5 2) (4 7) = (9 2) (7 4) = 63 8 kg

So the younger brother ate (63 8) * (3 7) =

So my brother eats a lot.

Set the younger brother ate x kilograms.

x+2+5/2=x/(3/7)

Solution x=27 8

x>5/2

So my brother eats a lot.