(x ^ 2 + 2x) ^ 2 + x ^ 2 + 2x = 12 to solve the equation

(x ^ 2 + 2x) ^ 2 + x ^ 2 + 2x = 12 to solve the equation

(X^2+2X)^2+X^2+2X=12
(x^2+2x)^2+(x^2+2x)-12=0
(x^2+2x-3)(x^2+2x+4)=0
Because x ^ 2 + 2x + 4 = (x + 1) ^ 2 + 3 > 0
So x ^ 2 + 2x-3 = 0
(x+3)(x-1)=0
So x = - 3 or x = 1

Solving equation: 2x / 3 = x ^ 2 / 12 + 3 / x ^ 2 + 4 / X
Please write down the method in detail

The denominator is removed, and the reduction is x ^ 4-8x ^ 3 + 48x + 36 = 0. The factorization is x ^ 4-8x (x ^ 2-6) + 6 ^ 2 = (x ^ 2-6) (x ^ 2 + 6) - 8x (x ^ 2-6) = (x ^ 2-8x + 6) (x ^ 2-6) = 0, then (x ^ 2-8x + 6) = 0, (x ^ 2-6) = 0; (x ^ 2-8x + 6) = 0, that is, (x-4) ^ 2 = 10, so X1 = 4 + √ 10, X2 = 4 - √ 10, and the solution (x ^ 2-6) = 0

Solving equation (2x + 3) ^ 2-4 (2x + 3) X-12 = 0

（2x+3)^2-4(2x+3)x-12=0
(2x+3-6)(2x+3+2)=0
(2x-3)(2x+5)=0
x1=3/2 x2=-5/2

Find the minimum value of a which makes x + y ≤ ax + y (x > 0, Y > 0) constant

Since the value of a is a positive number, the square of both sides of the known inequality is: x + y + 2XY ≤ A2 (x + y), that is, 2XY ≤ (A2-1) (x + y), ① ﹥ x, Y > 0, ﹥ x + y ≥ 2XY, ② if and only if x = y, there is an equal sign in ②. Comparing ① and ②, the minimum value of a satisfies A2-1 = 1, ﹥ A2 = 2, a = 2 (because a > 0), and the minimum value of a is 2

A pile of coal burned one sixth of it in November and two ninth of it in December, burning a total of 2.1 tons in two months. How many tons of coal is there in this pile?

﹙1／6﹚＋﹙2／9﹚＝7／18
2.1 △ 7 / 18 = 0.3 × 18 = 5.4 (ton)

Two questions about one variable quadratic inequality of senior high school mathematics compulsory 5
1. Let m = {x | x ^ 2-2x-3 ＞ 0}, n = {x | x ^ 2 + ax + B ≤ 0}, if M ∪ n = R, m ∩ n = (3,4], then a + B =?
2. If the inequality 2x ^ 2-3x + 5 > 0 has a solution in the interval [2,3], find the value range of the real number K

First question
Because the solution of M is: x > 3 or X

A travels 48 kilometers more than B. It is known that the speed ratio of a and B is 7:5. Find the distance between East and West stations

When the speed ratio is 7:5, the distance ratio is 7:5
So a is 7 / (7 + 5), B is 5 / (7 + 5)
7 / (7 + 5) - 5 / (7 + 5)
So the distance is 48 △ [7 / (7 + 5) - 5 / (7 + 5)] = 288km

3 / 8 (x + 1) - 1 ＞ 2 / 2 x-5-x solution inequality

3/8(x+1)-1>(x-5)/2-x
3/8x+x/2>-5/2+1-3/8
7/8x>-3/2-3/8
x>-15/7

The distance between a and B is 660 km. A passenger car and a freight car depart from a and B at the same time. The passenger car runs 42.5 km per hour, and the freight car runs per hour
The distance between a and B is 660 km. A passenger car and a freight car leave each other at the same time. The passenger car runs 42.5 km per hour and the freight car 34.5 km per hour. After a few hours, the distance between the two cars is 44 km?

(660-44) / (42.5 + 34.5) = 8 hours

If vector a = (x, 2,1), vector b = (- 3, x ^ 2, - 5), and the angle between vector a and vector B is obtuse, then the value range of X is?
Why should vector a and vector b not be parallel? Is it related to the word "if" in the title? If it doesn't mean "if", is it necessary to reverse the title when I see it? I'm very puzzled. Also, why do I want to reverse the title when I do other topics when I can't figure out this topic? Sometimes a very simple topic is very complicated, What am I supposed to do?

If vector a = (x, 2,1), vector b = (- 3, x ^ 2, - 5), and the angle between vector a and vector B is obtuse, then the value range of X is?
Analysis: let the angle between vector a and vector b be θ (π / 2)