1. If x (2) + X-2 = 0, then x (3) + 3x (2) - 2009= 2. The maximum value of equation 4-A (2) - 2ab-b (2) is Square in brackets!

1. If x (2) + X-2 = 0, then x (3) + 3x (2) - 2009= 2. The maximum value of equation 4-A (2) - 2ab-b (2) is Square in brackets!

First question
From the known x2 = 2-x
x3+3x2-2009
=x*x2+3x2-2009
=x(2-x)+3x2-2009
=2x-x2+3x2-2009
=2x+2x2-2009
=2x+2(2-x)-2009
=4-2009=-2005
Second question
4-a（2）-2ab-b(2)
=4-（a+b)2≤4
So the maximum is 4

Inequality, a few fill in the blanks!
1. If the minimum integer solution of 3 (1-x) > 2 (x + 9) is the solution of the equation 3x AX = 6, find the value of 6A
2. The solution set of inequality (5-a) x ≥ a-5 (a-5) is_____ The solution set of inequality (5-a) x ≥ a-5 (a > 5) is_____ .
3. When a ＜ 0, the solution set of inequality ax ＜ - 3 is_____ When a ＞ 0, the solution set of inequality ax ＜ - 3 is_____ .
4. If the solution set of inequality (a + 1) x < A + 1 about X is x > 1, then the value range of a is______ .
5. If 1-2x ≥ X-5 holds, the positive integer solution is________ .
6. Find the common part of the solution set of inequality 5x-1 ＞ 3 (x + 1) and 1 / 2x-1 ＜ 7-3 / 2x
Good answer,

Question 1: 3 (1-x) > 2 (x + 9)
3-3x>2x+18
-5x>15
x3/a (2):x

The convoy will travel 60km per hour to the disaster area, and reach the disaster area in 7.5 hours. When it comes back, it will travel 50km per hour. How long can it take to return

If x hours can be returned, then:
50x=60*7.5
x=9
That is, 9 time can return

In the "quantity and unit" column of the customs declaration form, how to distinguish and fill in the legal first unit of measurement, the legal second unit of measurement and the transaction unit of measurement?

Legal first unit of measurement and second unit of measurement are at the back of the code book, such as "set / kg", then "set" is the first unit of measurement, and "kg" is the second unit of measurement
The transaction unit of measurement is the quantity and unit of your actual import

Solving 80% x-3 / 5 = 2 / 5x equation

4/5x-2/5x=3/5
2/5x=3/5
x=3/5×5/2=3/2

As shown in the figure, a cuboid is cut into three sections on average along the length, each section is 2 meters, and the surface area is increased by 16 square meters. What is the volume of the original cuboid?

A: the volume of the original cuboid is 24 cubic meters

How to make their total number equal to 24

(1+7)×(9÷3)=24

The square ABCD is folded into a dihedral angle b-ac-d along the diagonal AC. E and F are the midpoint of AD and BC respectively, and O is the center of the square. The size of EOF after folding is calculated
I'm completely dizzy

The answer is 120 degrees
Connect BD
Take the midpoint of BD as G
Let the side length of a square be 1
Because b-ac-d is a straight dihedral angle
Then in the triangle BOD
The angle BOD is 90 degrees
We can calculate og = 1 / 2
And gfeo is the midpoint of BD BC ad AC
So eg = GF = fo = od = 1 / 2
So the quadrilateral gfoe is rhombic and the fog is equilateral triangle
So the angle foe = 120 degrees

With 2, 5, 0 and 9, we can make up several different four digit numbers

2059209522509259029052950; in the same way, there are 6 for 5 in the thousand, 6 for 9 in the thousand, and 0 cannot be placed in the thousand, so there are 18

It's a new definition of operation!
I forgot to copy the title
New definition operation:
A & B = axb-a + B + 1 find the value of (- 3) & 4
It must be fast! Today!

（-3）&4=-3x4-(-3)+4+1=-4