A unit marches for two days, covering a total of 78km. The average speed of the unit on the first day is 1.5km faster than that on the second day. If the unit marches for four hours on the first day and for five hours on the second day, what are the average speeds of the two days?

Suppose the average speed of March on the first day is x km / h, and the average speed of March on the second day is y km / h. from the meaning of the question, we get: X − y = 1.54x + 5Y = 78, and the solution is: x = 9.5y = 8. A: the average speed of March on the first day is 9.5km/h, and the average speed of March on the second day is 8km / h

Help me to do the following math problems in grade one
1. One column number: - 2,4, - 8,16
The nth number (n is a positive integer) is_____ .
2. If ▏ X-1 ▏ + (y + 2) & sup2; = 0, then X-Y=_ .

1. The N-1 power of - 1 times the root 2
2. Because ▏ X-1 ▏ + (y + 2) & sup2; = 0
So X-1 = 0, y + 2 = 0
So x = 1, y = - 2
So X-Y = 1 - (- 2) = 3

Who knows how to do the following math problem?
A class organized 25 League members to donate money to the disaster area, of which the amount of donation was 10 yuan for 5 people, 5 yuan for 10 people, 2 yuan for 5 people, and 1 yuan for each other. What is the percentage of the group members who donated 10 yuan to the total number of donors?

You seem to have asked a question once!
There are 5 people with 10 yuan;
Total number of donors: 25
5/25=20%

What is orthophoto?

The original remote sensing image has different degrees of distortion and distortion due to the influence of internal state change of sensor (optical system distortion, scanning system nonlinearity, etc.), external state (such as attitude change) and surface condition (such as earth curvature, topographic relief) when imaging. The geometric processing of remote sensing image not only extracts spatial information, but also improves the accuracy of remote sensing image, For example, the contour line can be drawn; the gray level of the image can also be resampled according to the correct geometric relationship to form a new orthophoto. The orthophoto production is mainly carried out by special equipment, such as flat ground center projection aerial photos, which can be corrected by optical mechanical corrector, For example, all kinds of Opto mechanical differential correctors and NC analytic orthophoto projectors (OR-1 and plani-comp Z2 are commonly used). Due to the complex dynamic conditions in the image formation process, all digital image correction or opto mechanical and digital hybrid image correction are usually used to produce orthophoto images, The Orthophoto Image can be directly used for image interpretation, measurement and thematic mapping, serving for resource and environment investigation and research, and also for making various image maps and map updating

Party A and Party B depart from a and B at the same time. Party A travels 36km per hour, and Party B travels 20% of the whole journey per hour. When the two cars meet, the distance ratio of Party A and Party B is 3:2. Find the distance between a and B

Speed ratio of a and B = distance ratio of a and B = 3:2
B speed = 36 △ 3 × 2 = 24km
A. B distance between the two places
24÷20%=120km

Simplify the square of a - (B-C) square △ the square of (a + b) - the square of C

[square of a - (B-C) square] / [square of (a + b) - square of C]
=[(a+b-c)(a-b+c)]÷[(a+b+c)(a+b-c)]
=(a-b+c)/(a+b+c)

Li Wei rides a motorcycle from home to the railway station. If he travels 30 kilometers per hour, he will be 15 minutes earlier than the train. If he travels 18 kilometers per hour, he will be 15 minutes later than the train's departure time. If Li Wei plans to arrive at the railway station 10 minutes before the train leaves, what's the speed of his motorcycle at this time?

Let the departure time of the train be x hours. From the meaning of the question: 30 (x-1560) = 18 (x + 1560), the solution is x = 1. Let Li Wei's cycling speed be y kilometers per hour, y = 30 × (1 − 1560) 1 − 1060 = 27. Therefore, Li Wei's cycling speed is 27 kilometers per hour

It is known that a = a + 2, B = a ^ 2-A + 5, C = a ^ 2 + 5a-19, where a > 2

A-B=-a^2+2a-3
b^2-4ac

The speed of a car going up the mountain is 30 kilometers per hour, and the speed of a car going down the mountain is 60 kilometers per hour (return according to the original road). The average speed of a car going down the mountain is ()
Kilometers.
A school of 30 students to spring outing, the school gave each person a row of yogurt, each row of 6 bottles. The store stipulates that "every five empty bottles can be replaced by one bottle of the same yogurt". The 30 students drink the yogurt and then change it. They can exchange () bottles of yogurt at most. Formula

The speed of the car uphill is 30km / h, the speed of the car downhill is 60km / h (return according to the original road). The average speed of the car downhill and downhill is (45km)
(30 + 60) △ 2 = 45 km
I wish learning progress, hope to adopt do not understand, welcome to ask

Given that x = 1 is the solution of the equation x 2A = 5, it is necessary to find the value of (2a 1) (2a-1) - A (4a-1)

Consider that the equation is 2aX = 5, and find the value of (2a-1) (2a-1) - A (4a-1)
X = 1 is the solution of the equation 2aX = 5
Substituting x = 1, we get
2a=5
a=5/2
(2a-1)(2a-1)-a(4a-1)
=4a^2-4a+1-4a^2+a
=-3a+1
=-15/2+1
=-13/2

A unit marches for two days, covering a total of 78km. The average speed of the unit on the first day is 1.5km faster than that on the second day. If the unit marches for four hours on the first day and for five hours on the second day, what are the average speeds of the two days?