On the number axis, points a and B represent rational numbers a and B respectively. The origin is just the midpoint of AB, a / 2012b=

On the number axis, points a and B represent rational numbers a and B respectively. The origin is just the midpoint of AB, a / 2012b=

Points a and B represent rational numbers a and B respectively. If the origin is just the midpoint of AB, then a + B = 0 and a / b = - 1
A of 2012b = A / (2012b) = - 1 / 2012

3/1*2+3/2*3+3/3*4+…… +3/99*100.
If you write the following two questions,
5/6+11/12+19/20+29/30+41/42=？
(9 2 / 7 + 7 2 / 9) / (5 / 7 + 5 / 9) =?
By 15:30

=3*（1-1/2+1/2-1/3+…… +1 / 99-1 / 100) = 3 * (1-1 / 100) = 3 * (99 / 100) = 297 / 100 = 2.97 question 2 = 1-1 / 6 + 1-1 / 12 + 1-1 / 20 + 1-1 / 30 + 1-1 / 42 = 5 - (1 / 2-1 / 3 + 1 / 3-1 / 4 + 1 / 4-1 / 5 + 1 / 5-1 / 6 + 1 / 6-1 / 7) = 5 - (5 / 14) = 65 / 14 question 3 = (65 / 7 + 65 / 9) / (5 /

The application of the equation of one variable and one degree
In 2013, Shanghai continued to levy house property tax on the newly purchased houses whose total housing area per capita is less than 60 square meters; for the newly purchased houses whose total housing area per capita is more than 60 square meters, the house property tax will be levied every year on the excess area of the newly purchased houses. (tax payable = original value of the excess part of the newly purchased houses * (1-30%) * tax rate)
A family of three has a house of 100 square meters. If a new house of 180 square meters with a unit price of 30000 yuan / square meter is purchased, the house property tax rate of 10080 yuan should be collected

100 + 180 - 60 × 3 = 100 (square meters) new housing exceeding the original value
10080 = 30000 × 100 × (1-30%) × tax rate
Tax rate = 10080 ÷ [3000000 × (1-30%)]
=0.0048
=0.48%

If the square of x minus 13X plus 1 equals 0, then what is the second power of x plus one fourth power of X

X ^ 2-13 x + 1 = 0 X1 = [13 + √ (13 * 13-4)] / 2 = 6.5 + 0.5 √ 165x2 = 6.5-0.5 √ 165 when x = x1, x ^ 2 = 6.5x6.5 + 165 / 4 + 6.5 √ 165 = (169 + 165) / 4 + 6.5 √ 165 = 83.5 + 6.5 √ 165x ^ 4 = (83.5 + 6.5 √ 165) ^ 2 = 83.5 ^ 2 + 6.5 ^ 2 * 165 + 1085.5 √ 165 = 13943.5 + 1085

The two passenger and freight cars start from the two stations a and B at the same time, and run in opposite directions. When they start, the speed ratio of the two cars is 8:5. After they meet, the speed of the bus decreases by 3 / 8,
Increase by 25%, so that when the bus arrives at the second place, the truck is 210 kilometers away from the first place. How many kilometers are there between the two places?

When we meet, the speed of the bus is: 8 (8 + 5) = 8 / 13, that of the truck is: 1-8 / 13 = 5 / 13, that of the truck is: 1 + 25% = 5 / 4, that of the bus is: 1-3 / 8 = 5 / 8, that of the truck is: 5 / 4 × 5 / 8 △ 5 / 8 = 5 / 4, that of the truck is: 5 / 4 × 5 / 13 = 25 / 42, that of the truck is: 8 / 1

It is known that the sum of the maximum and minimum value of the function y = a ^ x on [- 1,0] is 3.1, the value of a is 2, if 1 ≤ a ^ 2 < 16, the value range of X is obtained
It is 1 ≤ a ^ x < 16

We need to discuss them separately,
（1）a>1,
Then ymax = a ^ 0 = 1
ymin=a^(-1)=1/a
There is 1 + 1 / a = 3
The solution is a = 1 / 2

The construction site needs to carry away a pile of soil, 60 vehicles a day, which can be completed in 15 days. Now it needs to be completed three days in advance, how many vehicles a day

A total of 60 * 15 = 900 cars will be transported
Three days in advance means 12 days
900 / 12 = 75 cars / day

For a cone and a cylinder of equal height and equal base, the sum of their volumes is 48 cubic decimeters. What are the volumes of the cone and the cylinder?

The volume of a cone with equal base and height is one third of that of a cylinder
What is the volume of a cylinder
48 ÷ (1 ＋ 1 / 3) = 36 (cubic decimeter)
What is the volume of a cone
36 × 1 / 3 = 12 (cubic decimeter)

What is the smallest fraction that can be divided by 3.4.5 at the same time, and what is the prime factor of this decomposition

It's 60
60=2*2*3*5

The square of 2A - the square of 3B - 4AB plus the square of 2A - AB + the square of 2B
Congeners

A? + B? - 2A + 6B + 10 = 0, (A-1) ^ 2 + (B + 3) ^ 2 = 0, a = 1, B = - 3, 2 times the 100th power of a minus 3 times b square = 2-3 * 9 = - 25