（2y+1）2+3（2y+1）+2=0．

（2y+1）2+3（2y+1）+2=0．

Let 2Y + 1 = T. then from the original equation, we can get T2 + 3T + 2 = 0, {(T + 1) (T + 2) = 0,} T + 1 = 0 or T + 2 = 0, we can get t = - 1 or T = - 2; ① when t = - 1, 2Y + 1 = - 1, we can get y = - 1; ② when t = - 2, 2Y + 1 = - 2, we can get y = - 32

Factorization: 3AB (5b ^ 2) - 4A
Urgent request!

3ab(5b^2)-4a
=15ab^3-4a
=a(15b^3-4)

Factorization of x2 + X4 + 1

x^4+x²+1
=x^4+2x²+1-x²
=(x²+1)²-x²
=(x²+x+1)(x²-x+1)

It is known that m and N are nonempty proper subsets of set I, and m and N are not equal. If n ∩ (∁ IM) = ∞, then m ∪ n = ()
A. MB. NC. ID. ∅

By means of Wayne's drawing, we can draw a set which satisfies the problem that m and N are nonempty proper subsets of set I, and m and N are not equal, if n ∩ (∁ IM) = 0. From the graph we can get: m ∪ n = M. so we choose a

In the isosceles triangle ABC, B and C are fixed points, and AC = BC, D is the midpoint of BC, and make a circle d with BC as the diameter?

90 degrees. Because the angle obtained by connecting a point on the circle with both ends of the diameter of the circle is not 90 degrees. It is not very difficult to draw a picture

Given the real numbers a, B ∈ {- 2, - 1,1}. Find the probability that the line y = ax + B and the garden X & # 178; + Y & # 178; = 1 have a common point?

The solution requires that the line y = ax + B and the circle X & # 178; + Y & # 178; = 1 have a common point, then, (A & # 178; + 1) x & # 178; + 2abx + B & # 178; - 1 = 0,
If △ = 4A & # 178; B & # 178; - 4 (A & # 178; + 1) (B & # 178; - 1) ≥ 0, then a & # 178; + 1 ≥ B & # 178
We can first calculate the opposite, a & # 178; + 1 < B & # 178;. Only b = 2, a = 1 or - 1, which satisfies this condition, has a probability of 2 / 9
Then, the probability that the line y = ax + B and the circle X & # 178; + Y & # 178; = 1 have a common point is 1-2 / 9 = 7 / 9

1 / [(e ^ 2x-1) ^ 1 / 2] DX for indefinite integral

Mathematical problem (process) (solved by arithmetic method)
1. There are 120 public primary and secondary schools in a certain district, of which 70% are primary schools, and the ratio of primary school to middle school is 7:2. How many of the three types of schools are there? 2. Xiaogang bought a jacket and a pair of pants in the 20% discount zone of the clothing mall, of which the pants cost 390 yuan. How much is the original price of the jacket?
Xiaogang spent 840 yuan to buy a jacket and a pair of trousers in the 20% discount zone of the clothing store. The trousers cost 390 yuan. How much was the original price of the jacket?

1. [120 * (1-70%)] / (7 + 2) = 4 middle school sports schools 4 * 7 = 28 primary school sports schools 4 * 2 = 8 public primary schools 120 * 70 = 84
2. The title is incomplete

On the rule of parallelogram
In the parallelogram rule, the effect of two components of force is equal to the effect of resultant force (it is proved by the rubber band experiment that the rubber band is not regarded as a particle). But why should the general object be considered as a particle? If a piece of wood is placed on the horizontal table, the resultant force of 1000N is 0, and the resultant force does not make the object deform The effect of force includes deformation and motion state. Other vectors such as displacement, such as 100m to the East and 100m to the west, do not need to regard the object as a particle
What's more, how can the experiment of rubber band be extended to general use?

First of all, let's talk about when an object is regarded as a particle. Case 1: the object is small enough to be ignored in the scale of study. (for example, an object that is not a particle is divided into many very small blocks, each of which is a particle). Case 2: although the object has shape and size, the volume can't be ignored, but

1
(1) The solution of the inequality 2x + a < 3 about X (a is a constant)
(2) If the sum of all positive integer solutions of inequality in (1) is 6, please write all positive integer solutions
(3) Under the condition of (2), if a is an integer, the value of a is obtained

(1) 2x