1. If 3x-2y = 0, then (x + y): (X-Y)=______

-5, let a (x + y) + B (X-Y) = 3x-2y, remove the brackets and merge the similar terms to get: a = B-3, A-B = 2, solving the equations can get, a = 1 / 2, B = 5 / 2, so by the formula: (x + y) / (X-Y) + B / a = a (x + y) + B (X-Y) / a (X-Y) = 0; so: (x + y) / (X-Y) + B / a = 0, so (x + y) / (X-Y) =

Inverse scale function, Pythagorean, quadrilateral, data analysis) common problems
It's the last difficult one in the common math questions in the second volume of the eighth grade of pep

Go to buy an enhanced version of one lesson and one practice! Do a problem for a few minutes

In the range of real number, a * b = 1a-1b, if x * (x + 2) = 2x, then x=______ ．

X * (x + 2) = 2x, i.e. 1 X-1 x + 2 = 2 x, i.e. 1 x + 1 x + 2 = 0, get x + 2 + x = 0, and get x = - 1. So the answer is: x = - 1

Fraction exercises of mathematics in grade two of junior high school

1. Given a + B = 2008, find the value of (a ^ 2-B ^ 2 + 2b-1) / [(a ^ 2-B ^ 2) + (a + b)]
2. If x is equal to its reciprocal, then the value of (x ^ 2-x-6) / (x + 3) / (x-3) / (x ^ 2 + X-6) is ()
A.-3 B.-2 C.-1 D.0

Given the fraction A & sup2; - 1 / (a + b) & sup2; - (1 + AB) & sup2;, Wang Qiang concludes that when a = ± 1, the value of this fraction is equal to 0. Do you think Wang Qiang's judgment is correct? Please explain the reason

No matter how many a and B are, the formula is not equal to 0

Find a mathematical fraction problem in the second semester of junior high school
Xiaoming goes to the savings office to handle business. There are 8 people in front of window a and window B. Xiaoming stands behind window a to handle business. X minutes later, window a goes to person a, window B goes to person a + 1, and at the same time, there are 2 people coming behind. To implement it, queue up behind window a, or go to window B to handle business, save time, and explain the reason

The time required for window a to handle one person's business is x / A. There were 8 people in the past, but now it has become 8-a. the time required for window B to handle one person's business is (8-A) * x / A. the number of people in the window is 8 - (a + 1) + 2, that is, 9-a
So the time needed is (9-A) * x / (a + 1) to compare the size of (8-A) * x / A and (9-A) * x / (a + 1) by subtracting B from a to get (2x * (4-A)) / a (a + 1). Because x is greater than 0, we discuss the time saving window when a < 4, the time saving window when a > 4, and the time saving window when a = 4
You can use a formula to express the specific writing process. This is an oral answer. It should be more clear

3 () 3 () 3 () 3 = 4. How can addition, subtraction, multiplication and division be equal to four

3 times 3 equals 9, plus 3 equals 12, and divided by 3 equals 4!

How to add, subtract, multiply and divide with 8 3's and add bracket?
That's 3 = 2010
You can add, subtract, multiply and divide, or add brackets. How can you get 2010?

If only the four operations of addition, subtraction, multiplication and division and brackets are used, it is impossible to get the result, because there is a factor of 67 in 2010, which is impossible to get through the four operations. Only by adding the power can we get the result. If we add the power, we can get the result
(3^3+3)*[(3/3+3)^3+3]=2010

1 3 6 10 15 21 84
6 14 24 36 50 66 12
1 2 3 4 5 6 7
So what's the rule in the numbers above
How to get 100? It needs to be calculated by formula
That pile of numbers is a table, such as 1 to 6 to 1, 3 to 14 to 2

The first line is the first number plus 2, the second number plus 3, the third number plus 4, and so on
Add 8 to the first number in line 2, 10 to the second number, 12 to the third number, and so on
The third line is each number plus one, and so on

When Xiaoxin calculates 357 + (252-a / 12), he first calculates the subtraction in brackets, and the result is 370. What is the correct result of this problem?

In fact, the solution to the equation is 357 + (252-a) / 12 = 370 according to Xiaoxin's calculation, so a = 96 can be obtained
Then the correct result is very easy 357 + (252-a / 12) = 601

1. If 3x-2y = 0, then (x + y): (X-Y)=______