How many prime numbers are there in 23, 25, 35, 32, 52, 53? What are the combined numbers

How many prime numbers are there in 23, 25, 35, 32, 52, 53? What are the combined numbers

Prime numbers are: 23,53
The total number is: 25, 35, 32, 52

Which are prime numbers 23, 25, 35, 32, 52, 53? Which are combined numbers

Prime number: 23,53
Total: 25, 35, 32, 52

We know that a and B are constants, and the inequality ax + B is greater than 0. When --, the solution set of the inequality is x greater than B / a?

∵ ax + B ＞ 0, the solution set is x ＞ - B / a (no sign change) ∵ a ＞ 0 (if there is sign change, then a ＜ 0)

ABC is an isosceles triangle, ab = AC, with two waists as the sides, making equilateral △ ADB and equilateral △ ace outward respectively. If ∠ DAE = ∠ DBC, then the degree of ∠ BAC is______ ．

∵ AB = AC, ∵ ABC = ∵ ACB, so 2 ∵ ABC + ∵ BAC = 180 °, ∵ equilateral triangle each internal angle is 60 °, ∵ DAE = ∵ DBC, ∵ 120 ° + ∵ BAC = 60 ° + ∵ ABC, and ∵ 2 ∵ ABC + ∵ BAC = 180 ° and ∵ BAC = 20 °. So the answer is: 20 °

There are 90 books in group A, B and C. if group a borrows 3 books from group B and gives 5 books to group C, the number of books in the three groups is exactly the same. How many books did each group have?

According to the stem analysis can be: group a original 30-3 + 5 = 32 (this), then group B is 30 + 3 = 33 (this) and group C is 30-5 = 25 (this) answer: A has 32, B has 33, C has 25

Experiment: verify the parallelogram rule of force
In this experiment, the tension of the rubber band is the resultant force, and the tension of the two spring dynamometers is the component force. Why

No
The pulling force of two spring dynamometers is a component force, and the resultant force should be the force measured by only one dynamometer in the next step (or the gravity of the weight when the dynamometer is not used)

A mathematical problem, need to answer the ideas and process!
There are some students in class 61 who take part in the sports meeting, among which 2 / 7 are girls and 20 are boys. It is known that 4 / 5 of the boys in the class took part in the sports meeting, and 9 / 23 of the class did not take part in the sports meeting. How many girls are there in this class?

The number of participants in the Games is: 20 / (1-2 / 7) = 28
The class size is: 28 / (1-9 / 23) = 46
Number of boys: 20 / (4 / 5) = 25
Number of female students: 46-25 = 21

1.1 root of equation and zero of function

The answer is not at home. Can I give it to you tomorrow? Where are you from? The exercise book is also famous teacher No.1

There should be complete steps and answers to the derivative problem in senior two mathematics
19. The known function f (x) = 1 / 5x * 5-a / 3x * 3 + (a + 3) x + A * 2 has f (x) '≥ 0 for any real number X. find the value range of real number a
20. Given that the curve C1: y = x * 2 and the curve C2: y = - (X-2) * 2, the line L is tangent to both C1 and C2, find the equation of the line L

19. Because f '(x) = x * 4-xa * 2 + (a + 3) > = 0
Let t = x * 2, then f '(T) = t * 2-At + (a + 3)
Because the quadratic coefficient is 1, greater than 0
So △ = a * 2-4x (a + 3)

Derivation of the necessary and sufficient condition of two collinear vectors x1y2-x2y1 = 0
Let a = (x1, Y1), B = (X2, Y2), where B ≠ 0, we know that a and B are collinear if and only if there is a real number Λ, so that a = Λb, expressed in coordinates as (x1, Y1) = Λ (X2, Y2), that is, X1 = Λx2, Y1 = Λy2
Now it's this Λ. I don't know how to eliminate it. Please tell me in detail,
How does Λ look like this? This is the Greek letter mu.

X1 = λ X2, Y1 = λ Y2, Division: X1 / Y1 = x2 / Y2, so x1y2 = x2y1
If Y1 = 0 or y2 = 0, then X1 = 0 or x2 = 0, the equation also holds