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The bus from a to B had to run for 7 hours. When the expressway was opened, the road was close to 30 km. The average speed increased by 30 km per hour. It took 4 hours to get to a and B
Original vehicle speed: 50 km / h
Current highway vehicle speed: 80km / h
Original distance: 350km
Current expressway distance: 320km
If a > 0, b > 0 and the three sides of a + the three sides of B = 2
If a + B = 9, then root Ab0, b > 0, then root ab
999... 9 (1998 9) * 999... 9 (1998 9) + 1999... 9 (1998 9) =? Simple calculation
Original formula = 999... 9 (1998 9) * 999... 9 (1998 9) + 1999... 9 (1998 9)
=999... 9 (1998 9) * (1000... 0 (1998 0) - 1) + 1000... 0 (1998 0) + 999... 9 (1998 9)
=999... 9000.. 0 (1998 9 to 1998 0) - 999... 9 (1998 9) + 1000... 0 (1998 0) + 999... 9 (1998 9)
=999... 9000.. 0 (1998 9 to 1998 0) + 1000... 0 (1998 0)
=1000... 0 (1998x2 zeros)
=1000... 0 (3996 zeros)
The total weight of the three piles of coal is 12 tons. If 1 / 2 tons are transported from the first pile and the second pile to the third pile respectively, the weight ratio of the three piles of coal is 3:2:1
How many tons?
The first batch: 12 ÷ (3 + 2 + 1) X3 + 1 / 2 = 6.5 tons
Second pile: 12 △ (3 + 2 + 1) x2 + 1 / 2 = 4.5 tons
The third pile: 12 ÷ (3 + 2 + 1) x1-1 / 2-1 / 2 = 1 ton
(3a+2b)(2a-3b)-(a-2b）（2a-b） a=-1.5 b=1/4
=6a-9ab+4ab-6b-(2a-ab-4ab+2b) =4a-8b =4*(-1.5)-8*(1/4) =17/2
Given that w = Z + I (Z belongs to c), and (Z-2) / (Z + 2) is a pure imaginary number, find the maximum value of M = | W + 1|Λ 2 + |w-1|Λ 2 and the value of W when m takes the maximum value
Let the point corresponding to 2 in the complex plane be a, - 2 corresponding to B, Z corresponding to Z point, then Z-2 / Z + 2 is a pure imaginary number if and only if the angle AZB is a right angle (the difference between the radiation angles of Z-2 and Z + 2), then Z is on a circle with ab as diameter, that is | Z | = 2, then | w-i | = 2m = | W + 1 | ^ 2 + | W-1 | ^ 2 = (W + 1) (conjugate of W + 1) + (W-1) (conjugate of W)
The fruit store delivered a batch of apples, 720 kg more than pears. The weight of apples is 1.8 times that of pears. Apples and pears each weigh several thousand grams
Let the pear be X
The result is: x + 720 = 1.8x
So x = 900
Pears are 900 kg, so apples are 1620 kg
The master and the apprentice process the same amount of the same machine parts at the same time. When the master processes half of the parts, there are 102 apprentices left. When the master finishes, the master will finish
The ratio is 5:4!
Before December 26th, 26th is OK!
Write out your ideas! The more detailed, the higher the score!
Set X for each person
The ratio is 5:4
When the master makes 1 / 2, that is, X / 2, the apprentice makes x-102
So x / 2: (x-102) = 5:4
5(x-102)=4×x/2
5x-510=2x
5x-2x=510
3x=510
x=510÷3=170
A: each person needs to make 170
Is there phase difference between current and voltage in alternating circuit with capacitor only
When the voltage changes according to the sinusoidal law, is the current image also sinusoidal? If not, what should be done
In a pure capacitor circuit, the current is 90 degrees ahead of the voltage. If the voltage waveform is sine, then the current waveform is Shexian
A unit will rent part of the houses along the street. The rent of each house in the second year is 500 yuan more than that in the first year
The rent of all houses is 96000 yuan in the first year and 102000 yuan in the second year. Can you find out the research object in this situation?
What is the object of study in context
Why? It has nothing to do with the number of houses
The rent of the house
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