Simple calculation (1 / 3-1 / 4) + (1 / 4-1 / 5) + (1 / 5-1 / 6)

(1/3-1/4)+(1/4-1/5)+(1/5-1/6)
=1/3-1/4+1/4-1/5+1/5-1/6
=1/3-1/6
=2/6-1/6
=1/6

How to calculate 5 / 6 (3 / 4 + 1 / 2)

5 / 6 (3 / 4 + 1 / 2)
=5 / 6 (3 / 4 + 2 / 4)
=5 / 6 * 4 / 5
=4 / 6
=2 / 3

(1 / 5 + 3 / 4) / (3 / 4-1 / 5) simple operation

(1 / 5 + 3 / 4) / (3 / 4-1 / 5)
=(4 / 20 + 15 / 20) / (15 / 20-4 / 20)
=19 / 20 ÷ 11 / 20
=19 / 20 × 19 / 11
=19 out of 11

Simple calculation of 1 / 5-3 / 4

1/4÷1/5-3/4
=5/4-3/4
=1/2

Solve the equation, 3 / X-5 / 540-x = 138

The question should be 3 / X-5 / (540-x) = 138
Multiply both sides of the equation by X (540-x)
3 (540-x) - 5x = 138x (540-x)
Have you studied quadratic equation of one variable?
Learn to be able to solve, and finally into the denominator of the equation to verify whether the denominator is not 0

(3 / 8) + (4 / 9)) * 8 * 9 how to calculate easily
It must be easy to calculate

( 3/8 + 4/9 ) X 8 X 9
= 8 X 9 X 3/8 + 8 X 9 X 4/9
= 3 X 9 + 4 X 8
= 27 + 32
= 59

With the continuous improvement of people's economic income and the rapid development of the automobile industry, more and more cars have entered ordinary families and become a new growth point of residents' consumption. According to the statistics of a city's transportation department, at the end of 2008, the city's car ownership was 1.5 million, and by the end of 2010, the city's car ownership had reached 2.16 million. (1) the city's car ownership from the end of 2008 to the end of 2010 (2) in order to protect the urban environment and ease the car congestion, the city's transportation department plans to control the total number of cars, requiring that the city's car ownership will not exceed 2.3196 million by the end of 2012. It is estimated that since the beginning of 2011, the number of scrapped cars will be 10% of the car ownership at the end of last year Calculate the city's annual number of new cars can not exceed how many million

(1) Suppose that the average annual growth rate of car ownership in this city is x (1 point). According to the meaning of the question, we get 150 (1 + x) 2 = 216 (2 points), and the solution is X1 = 0.2 = 20%, X2 = - 2.2 (not suitable for the question, rounding off). Answer: the average annual growth rate of car ownership in this city is 20%; (4 points) (2) suppose that the number of new cars in the city is y 10000 every year

A computer costs 5000 yuan. After 10% price reduction, the price is increased by 10%. How much is the current price

(5000-5000x10%) + (5000-5000x10%) X10% = 5000-500 + (5000-500) X10% = 4500 + 450 = 1950, the current price is 4950 yuan

Given the function f (x) = | x ^ - 1 | + x ^ 2 + KX, and the definition field is (0,2)
(1) Find the solution of the equation f (x) = KX + 3 on (0,2)
(2) If f (x) is a monotone function over the domain of definition (0,2), the value range of the real number k is obtained
(3) If the equation f (x) = 0 about X has two different solutions x1, X2 on (0,2), find the value range of K

When x is on (0,1), f (x) = KX + 1. When x is on [1,2], f (x) = 2x ^ 2 + kx-1. This is a piecewise function
(1) Let f (x) =... In two intervals If we take the equation f (x) = KX + 3, we can get that when x is on (0,1), there is no solution, when x is on [1,2], x = root 2
(2) When x is in [1,2], the function is a quadratic function with the symmetry axis X = - K / 4, so to keep the function increasing or decreasing in the whole domain, the symmetry axis must be on the left side of x = 1 or on the right side of x = 2. In the first case, monotone increasing, we know that when x is on (0,1), f (x) = KX + 1, then because of increasing, K is greater than 0 (if it is equal to 0, f (x) = 1 is a constant, increasing does not hold), So obviously, the axis of symmetry x = - K / 4 is on the left side of x = 0, then f (x) = 2x ^ 2 + kx-1 must be increasing in [1,2], so k > 0
In the second case, decreasing, then K0 or K is less than or equal to - 8
(3) If k = 0, then when x is on (0,1), f (x) = KX + 1 = 1, when x is on [1,2], the two solutions of F (x) = 2x ^ 2-1 = 0 are not in the domain, so K is not equal to 0
The quadratic function f (x) = 0, two A1 and A2 are listed, and the root formula is listed, that is - K + - root sign (square of K + 8) / 4
The intersection point of a function and X axis is a solution, that is - K / 1
(1) If the first-order function has an intersection with the x-axis on (0,1), then K is less than or equal to - 1. Then the symmetry axis of the second-order function is on the right side of x = 1 / 4, and the other solution is an intersection of the second-order function and the x-axis
If the axis of symmetry is to the left of x = 1 where x = - K / 4 is, then another solution must be A2. The formula - k-radical (square + 8) / 4 belongs to [1,2], and K is greater than or equal to - 3.5. Therefore, we can know that - 3.5 "k-1"
If the axis of symmetry is to the right of x = 2 where x = - K / 4 is, then K-8, then another solution must be A1. Similarly, we know that k-3.5 or 3.5, so K-8
(2) If there is no intersection point between the primary function and the x-axis on (0,1), then k > - 1, then the symmetry axis of the quadratic function is on the left side of x = 1 / 4. Obviously, the two solutions A1 and A2 of the quadratic function cannot be all on [1,2], so they are omitted
I'll give you an overview,

Simple calculation (1 / 3-1 / 4) + (1 / 4-1 / 5) + (1 / 5-1 / 6)