If the values of all the real numbers x that are meaningful to the fraction ax + 7 / BX + 11 remain unchanged, what is the value of a / A + B?

(ax+7)/(bx+11)
First of all, if there is 0 in a and B, then both of them must be 0
When a and B are not zero, we want to be able to reduce x, and change the formula to:
a(x+7/a)/(b(x+11/b))
So we only need 7 / a = 11 / B to get rid of X
To sum up, 11a = 7b
Then a / (a + b) = 7 / 18

Please write an application problem, so that the unknown number x satisfies the following fractional equation 2 / x + 3 / X-2 = 1

2/x+3/x-2=1
Multiply both sides by an X at the same time
We get 2 + 3-2x = X
We get 3x = 5
So x = 5 / 3

If the number of times to square the fraction x + 2 / x into an integral and a molecule is less than the sum of the fractions of the molecule, the correct answer is（

x^2/(x+2)=[(x^2-4)+4]/(x+2)
=[(x+2)(x-2)+4]/(x+2)
=(x-2)+4/(x+2)

1. Given 1 / A-1 / b = 1, find the value of fraction (2a + 3ab-2b) / (a-2ab-b)
2. Given X / 3 = Y / 2 = Z / 5, find the value of fraction (XY + YZ + ZX) / (x ^ 2 + y ^ 2 + Z ^ 2)
3. Xiaohui is sitting on the bus driving at a constant speed, and noticed that there are some billboards lined up evenly on the roadside. He uses his watch to look at several billboards passing by the window in one minute. He starts to look at his watch and ends to look at it in the center of two billboards, and multiplies the number of billboards passing by in one minute by K, which is exactly equal to the kilometers of the car per hour, Please calculate the distance between two billboards (expressed in an algebraic expression with k)

1 because 1 / A-1 / b = 1, both sides multiply AB to get B-A = AB, that is, B = AB + a
2A + 3ab-2b = AB + a band entry is reduced to ab
Similarly, a-2ab-b is - 3AB AB / - 3AB, and the answer is - 1 / 3
Suppose X / 3 = Y / 2 = Z / 5 = a, then x = 3A, y = 2A, z = 5A
Bring in (XY + YZ + ZX) / (x ^ 2 + y ^ 2 + Z ^ 2) = 31 / 38
3. Set the number of billboards that pass in one minute as a, and the speed of the car = a * K
Vehicle distance in 1 minute = vehicle speed * time (1 minute 1 / 60 hours)
Distance between two billboards = 1 minute driving distance / number of billboards swept in 1 minute
Answer: K / 60

Two practical problems in grade one of junior high school
①
-In recent years, the highway construction has a great development, effectively promoting the economic construction
A highway to be built needs bidding. Now there are two engineering teams, Party A and Party B. If Party A and Party B work together, it can be completed in 24 days at a cost of 1.2 million yuan; if Party A works alone for 20 days, and the rest is done by Party B, it will take another 40 days to complete, which will cost 1.1 million yuan
Q:
(1) How many days will it take for team a and team B to complete the project separately?
(2) How many ten thousand yuan will it cost each team to complete the project alone?
②
-A company needs to complete the decoration of the new office building within one month (31 days). If team a and team B work together for 12 days, it can be completed. If team a and team B work alone, the time for team a to complete alone is 2 / 3 of the time for team B to complete alone
(1) Ask for the time required for team a and team B to complete the project alone
(2) If team a is invited to carry out the construction, the company will pay 2000 yuan per day; if team B is invited to carry out the construction, the company will pay 1400 yuan per day
seek
A: Ask team a to complete the project independently;
B: Ask Team B to complete the project independently;
C: Team a and team B work together to complete the project
Which scheme costs less
Please use fraction method to solve, not binary

①
-In recent years, the highway construction has a great development, effectively promoting the economic construction
A highway to be built needs bidding. Now there are two engineering teams, Party A and Party B. If Party A and Party B work together, it can be completed in 24 days at a cost of 1.2 million yuan; if Party A works alone for 20 days, and the rest is done by Party B, it will take another 40 days to complete, which will cost 1.1 million yuan
Q:
(1) How many days will it take for team a and team B to complete the project separately?
(2) How many ten thousand yuan will it cost each team to complete the project alone?
(1) If it takes X days to set a, there are:
B efficiency = 1 / 24-1 / X;
20×(1/x)+40×(1/24-1/x)=1;
20/x+5/3-40/x=1;
20/x=2/3;
x=30;
B days = 1 △ 1 / 24-1 / 30 = 120 days;
② If a is set at x ten thousand yuan per day, there will be:
20x+40×（120-24x）÷24=110；
20x+200-40x=110；
20x=90；
x=4.5；
Party B's daily unit price = (120-24 × 4.5) △ 24 = 5-4.5 = 5000 yuan;
Individual price of a = 4.5 × 30 = 1.35 million yuan;
5 × 120 = 600000 yuan;
-A company needs to complete the decoration of the new office building within one month (31 days). If team a and team B work together for 12 days, it can be completed. If team a and team B work alone, the time for team a to complete alone is 2 / 3 of the time for team B to complete alone
(1) Ask for the time required for team a and team B to complete the project alone
(2) If team a is invited to carry out the construction, the company will pay 2000 yuan per day; if team B is invited to carry out the construction, the company will pay 1400 yuan per day
seek
A: Ask team a to complete the project independently;
B: Ask Team B to complete the project independently;
C: Team a and team B work together to complete the project
Which scheme costs less
(1) If B needs X days, then a needs 2x / 3 days
1/(2x/3)+1/x=1/12;
3/2x+1/x=1/12;
(3+2)/(2x)=1/12;
2x=60;
x=30;
So it takes 20 days for a and 30 days for B;
(2) A: cost = 20 × 2000 = 40000 yuan;
B: Cost = 1400 × 30 = 42000 yuan;
C: Cost = 12 × (2000 + 1400) = 40800 yuan;
So a is the least;
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2 junior one fraction application questions, fast
1. A job can be completed in 4 days with the cooperation of Party A and Party B. after their cooperation for 3 days, Party B has another task, and it took party a 1.5 days to complete it alone. How many days does it take for Party A and Party B to complete it alone?
2. The ratio of the difference between the annual number of newborn babies minus the annual number of deaths and the annual average population is called the annual natural population growth rate. If P is used to represent the number of newborn babies, q is used to represent the annual number of deaths, s is used to represent the annual average number, and K is used to represent the annual natural population growth rate, then the annual natural population growth rate k = (P-Q) / s
Change the formula into a known KSP and find the formula of P
A formula for finding s by changing KPQ into known KPQ
In 2003, there were 15.99 million births and 8.25 million deaths, with a growth rate of 6.01%. What is the average population in China?
Given that there were 129.27 million people in the last year, how many million people (accurate to 10000 people) were the total population at the beginning of the year

1. Party A and Party B work 1 / 4 of every day, so they complete 3 / 4 of every 3 days; the remaining 1 / 4 is completed by Party A, so 1 / 4 / 1.5 = 1 / 6; Party A completes 1 / 6 of every day; Party A completes 1 / 1 / 6 = 6 days, then Party B completes 1 / 4-1 / 6 = 1 / 12; Party B completes 1 / 1 / 12 = 12 days. You can regard this work of Party A and Party B as 1. 2. K = (P-Q) / s

The messenger should look forward to the post 2400 meters away from the camp to deliver the message, and then immediately return according to the original road. In this way, it takes 40 minutes to return to the camp from the start to the meeting. If the messenger's speed is 1.5 times of the speed when he comes back, ask him the speed when he delivers the message
Xiao Li and Xiao Jie do speed calculation problems together. Xiao Jie can do 4 more problems per minute than Xiao Li. As a result, Xiao Jie does 240 speed calculation problems at the same time, while Xiao Li only does 160. How many problems can Xiao Li do per minute?

1. Set the speed back to X
2400/(1.5x)+2400/x=40
x=100
1.5x=150m/min
A. the speed of his delivery is 150m / min
2. Let Xiao Li do X questions every minute
They spent the same time
240/(x+4)=160/x
x=8
Xiao Li can do 8 questions per minute

The calculation of fraction in the first grade of junior high school
Let ABC ≠ 0 and 3a + 2b-7c = 0.7A + 4b-15c = 0, find the value of 3A ^ 2-4b ^ 2-5c ^ 2 / A ^ 2 + 2B ^ 2 + 3C ^ 2

From 3A + 2b-7c = 0.7A + 4b-15c = 0, a = C, B = 2c are obtained
Substituting 3A ^ 2-4b ^ 2-5c ^ 2 / A ^ 2 + 2B ^ 2 + 3C ^ 2 = (3C ^ 2-16c ^ 2-5c ^ 2) / (C ^ 2 + 8C ^ 2 + 3C ^ 2) = - 3 / 2

Solving a mathematical problem about one variable Fractional Inequality
3X-4／2X+5≥1

Transfer term solution
3X-4／2X+5≥1
(3x-4 / 2x + 5) - 1 ≥ 0
(3x-4 / 2x + 5) - [(2x + 5) / (2x + 5)] ≥ 0
(X-9) / (2x + 5) ≥ 0 because 2x + 5 is on the denominator, so 2x + 5 is not equal to 0
So the inequality solution is x ≥ 9 or X

A mathematical problem about inequality of grade two in junior high school
In a blasting operation, Wang Hua is responsible for lighting the fuse. In order to ensure safety, Wang Hua should leave the blasting point at least 120 meters before blasting. If the burning speed of the fuse is 0.75 cm / s and Wang Hua's leaving speed is 4.5 m / s, how many cm of the fuse is needed to ensure Wang Hua's safety? It's better to have a process
Take out the results

At least x cm fuse is needed to ensure Wang Hua's safety
120/4.520
A: at least 20 cm fuse is needed to ensure Wang Hua's safety

If the values of all the real numbers x that are meaningful to the fraction ax + 7 / BX + 11 remain unchanged, what is the value of a / A + B?