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It's a difficult question Xiao Li bought back a batch of apples and priced them at 20% profit. After a few days of sales, only 75% of all the apples were sold. In order to sell the rest of the apples as soon as possible, Xiao Li decided to sell them at a discount. As a result, all the remaining apples were sold, and the total profit reached 85% of the plan. Do you know how much discount Xiao Li made?
The purchase price of apple is unit 1
The planned profit is 20%
After selling 75% of all apples, the profit is 20% × 75% = 15% of the plan
The profit is 20% × 85% = 17%
After discount, the profit is 17% - 15% = 2% of the plan
How much discount (20% - 2%) / 20% = 0.9 = 10%
Given x + Y-3 + Lxy + X + y-2l = 0, find the value of X / y + Y / X
Given the absolute value of √ x + Y-3 + XY + X + y-2l = 0, find the value of X / y + Y / X
The root sign and absolute value are greater than or equal to 0
If the sum is 0, it is equal to 0
So x + Y-3 = 0
xy+x+y-2=0
therefore
x+y=3
xy=2-(x+y)=-1
So (x + y) & sup2; = 9
x²+y²+2xy=9
x²+y²=9-2xy=5
(x²+y²)/xy=-5
So x / y + Y / x = - 5
How to prove that y = (AX + n) / (BX + m) is not equal to a / b
Forget to add conditions --
Not equal to - M / b
But isn't this the implied condition of the original title? The denominator is not 0
Yes, and a is not equal to B
M n is not equal. It should be like this. The teacher talked about it in class, but I only wrote these notes. Now I can't understand it in review-
Can be equal to
For example, a = b = M = n
So y = 1 is equal to 1
We should add BN ≠ am
Suppose equal to
(ax+n)/(bx+m)=a/b
b(ax+n)=a(bx+m)
abx+bn=abx+am
bn=am
And BN ≠ am
So it can't be equal to
The set M = {(x, y) Lxy < 0, X ￡ R, y ￡ r} is
The set of all points in quadrant two or four in the plane rectangular coordinate system
Can we split a prat into several parts in Adams? How?
This is really not good
What are exponential coefficient, residual sum of squares, correlation coefficient and residual graph?
I don't quite understand what you mean. Can you make it clear?
The sum of the squares of the abscissa and ordinate of the vector is equal to 0
Why is the sum of the squares of the abscissa and ordinate of the vector in the plane rectangular coordinate system = 0?
From the scalar product formula of vector: a · B = | a | B | cos θ
∵ a ⊥ B ≁ cos θ = 90 degrees = 0
∴a·b=0 ①
Let a (x1, Y1) B (X2, Y2)
Then the formula a · B = x1x2 + y1y2 = 0
Given that the sum of squares of four positive integers is 2009, and the ratio of three integers is 2:3:6, then the four integers are?
Starting from 2:3:6, multiply the proportion by 7 to get 14:21:42, and 14 & # 178; + 21 & # 178; + 42 & # 178; = 2401, which is larger than 2009,
So this number must be less than or equal to 6
Multiply the proportional number by 6 to get 12:18:36, and 12 & # 178; + 18 & # 178; + 36 & # 178; = 17642009-1764 = 245, which can't be an integer
Multiply the proportion by 5 to get 10:15:30, and 10 & # 178; + 15 & # 178; + 30 & # 178; = 12252009-1225 = 784, √ 784 = 28
Multiply the proportional number by 4 to get 8:12:24, and 8 & # 178; + 12 & # 178; + 24 & # 178; = 7842009-784 = 1225, √ 1225 = 35
The same times of 3, 2 and 1 are not in line with the meaning of the question
So these four numbers are 10, 15, 30, 28 or 8, 12, 24, 35
How to calculate regression equation with calculator
Different calculators have different operations. Some calculators can't do regression calculation without regression calculation function. (for example, the scientific calculator in Windows)
If the calculator has the function of regression calculation, type the calculator in the regression calculation file (with the "mode" key, sometimes the "1", "2" and "3" keys are added, and the operation is different due to different calculators)
Input data, the input method of the f82 calculator is: "Xi"; ","; "Yi"; "data";. Until the data is input
Call out the value of a and the value of B, then the regression equation is y = BX + a (for the f82 calculator)
Who knows how to calculate regression equation with scientific calculator?
Regression analysis is a kind of statistics, which studies the relationship between two related variables and is a supplement to the functional relationship. Because the two variables are only related but not functional, the regression equation obtained is only an estimate of the actual situation of the two variables, Csio fx-991es you click the mode key 3: stat statistics 1-var univariate statistics a + BX linear regression - + CX2 quadratic regression INX logarithmic regression e ^ x exponential regression A. B ^ x exponential regression A. x ^ B power regression 1 / X reciprocal regression
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