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Yesterday afternoon, Mr. Zhang assigned a math problem. In the evening, I racked my brains and couldn't figure out how to solve it, Fill in a poem My grandfather's 70th birthday is congratulated by all my relatives and friends. I wish my grandfather happiness and longevity. But my grandfather sighed () I'll stop him soon () grandfather, your body is stronger than young people!
1. No way out
2. "The setting sun is infinitely good, just near dusk"
3. "Mo Dao, Sangyu, the clouds still fill the sky in the evening"
There was a math problem last night. I racked my brains and couldn't figure out how to solve it. Just when I was (), my father came over and I was suddenly enlightened
It's poetry
There was a math problem last night. I racked my brains and couldn't figure out how to solve it. Just when I (the mountains are heavy and the waters are full of doubts and there is no way out), my father came to me and I was enlightened by his advice
If it is all, it should be:
There was a math problem last night. I racked my brains and couldn't figure out how to solve it. Just when I was (), my father came up to me. With his help, I was suddenly enlightened
The answer is: there was a math problem last night. I racked my brains and couldn't figure out how to solve it. Just when I (the mountains are heavy and the waters are complex and there is no way out), my father came to me. With his help, I suddenly became enlightened. It's really another village!
Last night, there was a math problem that I racked my brains and couldn't figure out how to solve. Just as I was, my father passed by
Last night, there was a math problem that I racked my brains and couldn't figure out how to solve. Just when I was at the end of my life, my father came over and said, "there's another village with dark willows and bright flowers."
Everyone give a guide, the son's homework test live his father
1. Given the polynomial (2k-3) x + 2x ^ 2-3K (where x ^ 2 is the square of x), the value of this polynomial is independent of K, try to find the value of X
2. If 4x ^ 2 + 15x-5 = 0, find the value of the algebraic formula (- 15x ^ 2-18x + 9) - (- 3x ^ 2 + 19x-31)
(2k-3)x+2x*x-3k
=2xk-3x+2x^2-3k
=(2x-3)k+2x^2-3x
The value of K has nothing to do with the value of K
So the coefficient of K is 0
So 2x-3 = 0
x=3/2
x*x+x-1=(3/2)*(3/2)+3/2-1=9/4+3/2-1=11/4
If 4x ^ 2 + 15x-5 = 0, find the value of the algebraic formula (- 15x ^ 2-18x + 9) - (- 3x ^ 2 + 19x-31)
(-15x^2-18x+9)-(-3x^2+19x-31)
=-15x^2-18x+9+3x^2-19x+31
=-12x^2-37x+40
=-3(4x^2+15x-5)+8x+25
=8x+25
4x^2+15x-5=0
There are two cylindrical containers a and B. at first, container a contains 2 liters of water, and container B is empty. Now, water is injected into the two containers at the rate of 0.4 liters per minute. After 4 minutes, the water surface height of the two containers is equal. It is known that the bottom radius of container B is 5 cm, and what is the diameter of container A & nbsp; bottom? The thickness of the container is not taken into account
A container water volume: 2 + 0.4 × 4 = 2 + 1.6 = 3.6 (L), B container water volume: 0.4 × 4 = 1.6 (L), 3.61.6 = r222, 3.6 × 4 = 1.6r2, & nbsp; 1.6r2 = 14.4, & nbsp; R2 = 9, so r = 3; a: the bottom radius of a is 3cm
What's the biggest math problem in history?
Xiao Ming has 15 yuan, Xiao Hong 45 yuan, and Xiao Zhang how much?
Mathematical problems about work efficiency
If a certain work needs a day for Party A and Party B to cooperate, B days for Party A to do it alone, and C days for Party B to do it alone
Does 1 / B + 1 / C = 1 / a hold?
1 divided by (1 / A-1 / b)
A math problem I want to do for half a day --~
There is a batch of salt in the warehouse. After 60% of the total amount is transported, another 130 tons are transported. At this time, the total amount of salt is 55 tons more than that of the original batch. How many tons is the warehouse now
There is a warehouse for X tons of salt
（1-60%）x+130=x+55
0.4x+130=x+55
x-0.4x=130-55
0.6x=75
x=125
Now there is salt = 125 + 55 = 180 tons
I haven't thought about a math problem for a long time. Can I help you
The product of four continuous natural numbers is 43680,
What are the four natural numbers?
First, find out the square root of 43680, which should be about 210, then find out the square root of 210, which should be about 15, then we can know that these four numbers are around 15, and then we can get 13,14,15,16 by simple calculation according to 13,14,15,16,17
1. There is a pool. It takes 24 minutes to turn on tap a and 36 minutes to turn on tap B. now turn on tap a for a few minutes, then turn off tap a and turn on tap B to fill the pool. It is known that tap B has 26 minutes more than tap A. how many minutes has it taken to fill the pool?
2. There are 50 students to visit, 1.2 yuan for each person by tram, 4 yuan for each person by minibus, and 6 yuan for each person by subway. These students share a fare of 110 yuan. How many of them are there by minibus?
3. The motorcycle race is 281 kilometers long and divided into several stages, Some are composed of an uphill road (3 km), a level road (4 km), a downhill road (2 km) and a level road (4 km); some are composed of an uphill road (3 km), a downhill road (2 km) and a level road (4 km)?
4. A and B leave from a and B at the same time. Car a travels 60 kilometers per hour, while car B travels 10% of the whole journey per hour. When car B reaches 13 / 24 of the whole journey, car a has already traveled 5 / 8 of the whole journey?
First question
We regard the filling pool as a whole. 1. Tap a fills the pool in 24 minutes, which is 1 / 24 of every minute. Tap B fills the pool in 36 minutes, which is 1 / 36 of every minute. Now tap a turns off after a period of time and fills it with tap B. tap B turns on 26 minutes more than tap A. We think that tap B turns on 26 minutes alone, except for 26 / 36 of water filling, the other 10 / 36. The two taps turn on the same time, The efficiency is 1 / 24 + 1 / 36 = 3 / 72 + 2 / 72 = 5 / 72, the same time of opening two faucets is (10 / 36) / (5 / 72) = 20 / 5 = 4 minutes, the total time of filling the pool is 4 + 4 + 26 = 34 minutes
Second question
Can you solve the equations? Let me change the algorithm first. The tram fare is 1.2 yuan, the minibus fare is 4 yuan, and the subway fare is 6 yuan. If all 50 students take the tram, it's only 1.2x50 = 60 yuan, but the actual 110 yuan is 50 yuan more. Among them, the minibus fare is 2.8 yuan more than the tram, and the subway fare is 4.8 yuan more than the tram
Let's see, 50 = 0.4x125, 2.8 = 0.4x7, 4.8 = 0.4x12, see 125 + 7 = 120 + 12, we think of 12x11-12x7 = 12x4 = 48, so 125 = 48 + 77 = 12x4 + 7x11, that is 50 = 4.8x4 + 2.8x11
There are 11 students who take the minibus, 4 students who take the subway, and the rest 35 students take the tram. Check and calculate, 1.2x35 + 4x11 + 6x4 = 42 + 44 + 24 = 110, exactly
The third question
There are two kinds of track in motorcycle race. The first kind of track has four sections: 3km uphill, 4km level road, 2km downhill and 4km level road. The length of this kind of track is 3 + 4 + 2 + 4 = 13km. The second kind of track has three sections: 3km uphill, 2km downhill and 4km level road. The length of this kind of track is 3 + 2 + 4 = 9km, The other 3 km uphill, 2 km downhill are the same
The algorithm of the second question just now, if 25 uphill roads are all 9 km of the second track, the whole course is 25x9 = 225 km, but there are 281 km, 281-225 = 56, 56 / 4 = 14. In this way, the first track of 13 km has 14 sections, and the second track of 9 km is 11 sections. Check and see, 13x14 + 9x11 = 182 + 99 = 281, exactly
The fourth question
The distance between the two places is considered as a whole. Car a travels 60 kilometers per hour, and car B travels 1 / 10 per hour. When car B reaches 13 / 24 of the whole journey, car a travels 5 / 8 of the whole journey. Let's see, how long does it take car B to reach 13 / 24?
(13 / 24) / (1 / 10) = 130 / 24 = 65 / 12 hours. Car a starts at the same time. The distance during this period accounts for 5 / 8 of the whole journey. This 5 / 8 is 60x 65 / 12 = 5x65, and the whole journey is 5x65 / (5 / 8) = 8x5x65 / 5 = 8x65 = 520km
After checking and calculating, the distance between the two places is 520 kilometers. Car B travels 52 kilometers per hour, and it takes (520x 13 / 24) / 52 = 130 / 24 = 65 / 12 to get to 13 / 24 of the whole journey. Car a takes (520x 5 / 8) / 60 = 260 / 48 = 65 / 12 to get to 5 / 8 of the whole journey. The calculation results are correct
I have also put forward my ideas. If you are a junior high school problem and ask for equations, I hope you don't be lazy. Read my answers, get inspiration, and then work out the problem according to the requirements. To learn knowledge and master skills, we have to rely on our own practice,
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