Linear inequality (system) with one variable & linear equation system with two variables The traditional Chinese medicine preventive formula in the traditional Chinese medicine prevention plan for influenza A (H1N1) in Shandong Province is: Radix Pseudostellariae 6 g, Radix Ophiopogonis 3 G, Flos Lonicerae 3 G, soak in 200 ml to 300 ml boiling water for 30 minutes, take one dose (i.e. the dose of one formula) every day for 5 consecutive days (1) A drugstore only has enough winter wheat in stock. It costs 1800 yuan to buy 20 kg of Pseudostellaria heterophylla and 30 kg of honeysuckle in the market. It costs 1700 yuan to buy 30 kg of Pseudostellaria heterophylla and 20 kg of honeysuckle. What are the prices of Pseudostellaria heterophylla and honeysuckle in the market? (2) The drugstore plans to spend 15000 yuan to buy all the radix Pseudostellariae and honeysuckle, and all the Chinese medicine purchased will be used to make this kind of anti H1N1 formula. How many doses of this kind of Chinese medicine formula can be made at most? How many people can take it continuously?

(1) : Radix Pseudostellariae 30 yuan / kg, honeysuckle 40 yuan / kg
(2) Because winter wheat is enough, 15000 yuan is used to buy Radix Pseudostellariae and Flos Lonicerae, and because the ratio of medicinal materials is 2:1:1, the amount of Flos Lonicerae bought is the same as that of Radix Pseudostellariae
If the purchase price of Pseudostellaria heterophylla is x kg, the purchase price of honeysuckle is x kg
So 30x + 40x = 15000
70X=15000
X = 1500 kg / 7 = 1500000 g / 7
Because a formula takes 3 grams, it can be used for 500 000 formulas out of 7. Because one person uses 5 packages, it can be used for 100 000 people out of 7. Because it takes an integer, it can be used for 14 285 people
The second question may not be very accurate! Wrong, please understand!

What is 30 times 0.5 percent

30×0.5%=0.15

We know that the equation 3x + y is equal to 12 4x + ay is equal to 2 and has integer solution, so we can find the value of A
Better have a process. Float away

3x + y = 12 = = = > y = 12-3x is substituted into the following formula:
4X + ay = 2
4x+a(12-3x)=2
(4-3a)x=2-12a,a≠4/3
x=(2-12a)/(4-3a)=(16-12a+14)/(4-3a)=4+14/(4-3a)
y==12-3x=42/(4-3a)
As long as X is an integer, y must be an integer, that is, 14 / (4-3a) is an integer,
4-3a=±14,±7,±2,±1
Get:
a=6,2,11/3,5/3,1,2/3,-1,-10/3

5 / 7 * 37.5% + 1 / 7 * 3 / 8 + 3 / 8 divided by 7

5 / 7 * 37.5% + 1 / 7 * 3 / 8 + 3 / 8 divided by 7
=5/7×3/8+1/7×3/8+3/8×1/7
=﹙5/7+1/7+1/7﹚×3/8
=1×3/8
=3/8

Solve the equation, 3 / 4x-0.25 = 5 / 2

3x=10-1=9
x=3

40 and 2 / 3x39 and 1 / 3 are calculated by the square difference formula

=(40+2/3)×(40-2/3)
=40²-(2/3)²
=1600-4/9
=1599 and 5 / 9

In the triangle ABC, it is known that sina + sinc = 2sinb, and the difference between the maximum angle and the minimum angle is 90 degrees
Tell me why

Sinc = sin (A-90) = - Cosa COSC = cos (A-90) = sinasinasina + sinc = 2sinb = 2Sin (a + C) Sina + sinc = 2sinacosc + 2cosasincsina (2cosc-1) + sinc (2cosa-1) = 0sina (2S

1234 4123 3412 2341 calculate the following determinants

1234,4123,3412,2341
Step 1: add the second, third, and fourth columns to the first column
10 2 3 4
10 1 2 3
10 4 1 2
10 3 4 1
Step 2: subtract the first line from the second, third and fourth lines to get the
10 2 3 4
0 -1 -1 -1
0 2 -2 -2
0 1 1 -3
Step 3: double the third line and add the second line to the third line, and add the second line to the fourth line
10 2 3 4
0 -1 -1 -1
0 0 -4 -4
0 0 0 -4
Step 4: determinant value = 10 * (- 1) * (- 4) * (- 4) = - 160

If the vertex of the parabola y = x Λ 2 + 8x + C is on the X axis, then the value of C is ()

First, the parabola opens up if the vertex is on the x-axis
The minimum value of y = 0
That is, when x = - 4, y = 0
So C = 16

Factorization: 2-2 ^ 2-2 ^ 4 -... - 2 ^ 19 + 2 ^ 20

2-2^2-2^3-2^4-...-2^18-2^19+2^20=2^20-2^19-2^18...-2^4-2^3-2^2+2=2^19(2-1)-2^18...-2^4-2^3-2^2+2=2^19-2^18...-2^4-2^3-2^2+2=2^18...-2^4-2^3-2^2+2.=2^2+2=6