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Anonymous users2024-02-07One:11-3 times (m+n) mn
2. mn/m+n
2. 10a/10-a
3. s/（a-2）-s/a
4. （1）40x/（x+y）
2）40/y-40/x
5. 2ab/a+b
6.(a-b) squared - (a-squared-b-squared).
7.x (1+10 percent).
8.A multiplied by (1 + 15 percent) multiplied by (1 + 1 percent 15 percent) 919+m The second one will be said later, and now I have something.
10.n is an integer.
1）2n 2n+2 2n+4
2）2n+1 2n+3 2n+5
11.b is greater than a and a is not equal to 0
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Anonymous users2024-02-06You go to Jingyou.com to find out, there is a detailed process.
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Anonymous users2024-02-05It is known that if the inlet pipe of a 1200 liter pool is filled in 9 hours, the flow rate of the inlet pipe of a is 1200 9 = (400 3) liter hours.
It is known that if the 1200 liter pool is filled with the B inlet pipe in 10 hours, the flow rate of the B inlet pipe is 1200 10 = 120 (liter hour).
Suppose there were V liters of water in the original pool.
For the inlet pipe of A, drain water at the same time, and empty it in 3 hours, the amount of water discharged is: 3x(400 3)+v=400+v, and the flow rate of the drain pipe is: (400+v) 3 400 3+v 3
For the inlet pipe of A and B, drain at the same time, and empty in 5 hours, the amount of water discharged is: 5x((400 3)+120)+V, and the flow rate of the drainage pipe is: ((2000 3+600)+V) 5=400 3+120+V 5
Apparently there is, 400 3+v 3 400 3+120+v 5, v 3=v 5+120, 5v = 3v + 120x15, 2v = 120x15
That is: v=60x15=900
Answer: It turns out that there are 900 litres of water in the pool.
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Anonymous users2024-02-04The question of the civil servant, I failed in elementary school.
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Anonymous users2024-02-03Solution: The flow rate of the inlet pipe is: 1200 9 = (400 3) liters per hour The flow rate of the inlet pipe b is: 1200 10 = 120 liters per hour, and the original pool contains v liters of water.
For the inlet pipe of A, drain water at the same time, and empty it in 3 hours, the amount of water discharged is: 3x(400 3)+v=400+v, and the flow rate of the drain pipe is: (400+v) 3 400 3+v 3
For the inlet pipe of A and B, drain at the same time, and empty in 5 hours, the amount of water discharged is: 5x((400 3)+120)+V, and the flow rate of the drainage pipe is: ((2000 3+600)+V) 5=400 3+120+V 5
Apparently there is, 400 3+v 3 400 3+120+v 5, v 3=v 5+120, 5v = 3v + 120x15, 2v = 120x15
That is: v=60x15=900
Answer: It turns out that there are 900 litres of water in the pool.
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