The answer and process of the first question in the mathematics exercise book of Zhejiang Education Press

The answer and process of the first question in the mathematics exercise book of Zhejiang Education Press

Xiaomin and Xiaoqiang took part in a social practice during the holiday. The factory used whiteboard paper to make packing boxes. Each whiteboard paper was designed to make two box bodies or three box covers, and one box body and two box covers were just made into a packing box. In order to make full use of materials, the box body and box cover were just matched
Set X pieces of paper as the box body. (14-x) pieces of paper as the box cover
2X2x=3（14-x）
4x=42-x
X = 6 2x = 6x2 = 12~~~

The addition and subtraction of 7.3 fractions (2)
3/（x-2）（x+1）- 1/x-2
X / x + square of 1-x + square of 1 / x + X
The square of a / a - 1 + 1 / A + 1
3x / (x-3) + X / x-3, and find the value of the original formula when x = - 2
(cubic power of 1 / X - square of 1 / x) * cubic power of X / X-1
Square of X / 2-x - 4-x / square of X - 4x + 4
Wait. Before 9:30

The addition and subtraction of fractions (2) PS: x square = X2, x cube = X3... And so on 1: (1) 5A (2) a square, b square = (a2b2) 2: (1) a + B / AB (2) - 1 / 6x (3) 4AB + B / 4a2 (a square) 3: (1) 4m / (M + n) (m-n) (2) - 1 / x + 1 (3) - 1 / x2 + X (4) 1 / a-14:3x / (x -...)

The addition and subtraction of fractions (2)
Questions 5 and 6 plus sub question 3 of question 3

Addition and subtraction of fractions (2) PS: square of x = X2, cube of x = X3... And so on
1：（1）5a
(2) Square of a square of B = (a2b2)
2：（1）a+b/ab
（2）-1/6x
(3) 4AB + B / 4a2 (the square of a)
3：（1）4m/(m+n)(m-n)
（2） -1/x+1
（3）-1/x2+x
（4）1/a-1
4: The square of 3x / (x-3) + X / x-3
=The square of 3x / (x-3) + the square of x2-3x / (x-3)
=Square of x2 / (x-3)
When x = - 2
The original formula = the square of x2 / (x-3)
=4/25
5：（1） -1
（2）2/x-2
6: The original person is (X-2)
300/x-2-300/x
=300x/x2-2x-300x-600/x2-2x
=600/x2-2x
A: it is 600 / x2-2x yuan less than the original

Simple calculation of 0.46 times 10.1 minus 0.046

0.46 times 10.1 minus 0.046
=0.46x10.1-0.46x0.1
=0.46x(10.1-0.1)
=0.46x10
=4.6

A cube and a cuboid form a new cuboid. The surface area of the cuboid increases by 50 square meters
What is the surface area of the cube?

The area of one face of a cube is: 50 △ 4 = 25 / 2 square centimeter
The original surface area of the cube is: 25 / 2 × 6 = 75 square centimeters

Fourth grade summer garden riddles are typed
A door, three floors () a mountain, two chickens () plus grass, you can eat () 4:13 ()
Twelve points () can't remember () can't see () the teacher's surname is "Kuquan" (hit a surname) ()
One skim () ten skim () one big skim () another skim () ten thousand skim () one big point () another point ()
13 o'clock () 18 o'clock () a little bit in the mouth () leave a little bit () cut nine pieces () 3 divided by 2 = 1
And the number of how to move a match is 12041
(the formula he gave)
12=11-1=12041

A door, three floors (Yan) a mountain, two chickens (you) plus grass, you can eat (add) 4.13 (AO) 12 points (jade) can't remember (forget) have eyes can't see (blind) teacher surname "Kuquan" (play a surname) (white) a pai (factory) ten Pai (thousand) a big Pai (

Factorization: - 4m ^ 2n ^ 5 (X-Y) ^ 2 + 16Mn ^ 3 (Y-X) ^ 2-2m ^ n ^ 2 (Y-X) ^ 3

Original formula = - 4m ^ 2n ^ 5 (X-Y) ^ 2 + 16Mn ^ 3 (X-Y) ^ 2 + 2m ^ 2n ^ 2 (X-Y) ^ 3
=-2mn^2(x-y)^2[2mn^3-8n+(x-y)]
=-2mn^2(x-y)^2(2mn^3-8n+x-y)

The sum of natural numbers a, B, C and D is 45. The results of a + 2, B-2, C multiplied by 2 and D divided by 2 are the same. How much is ABCD?

It is known that a + B + C + D = 45
a+2=b-2=c*2=d/2
Let C be known,
be
a=2c-2
b=2c+2
d=4c
Substituting a + B + C + D = 2c-c + 2C + 2 + C + 4C = 45
That is 9C = 45
So C = 5
a＝2*5-2＝8
b＝2*5+2＝12
c＝5
d＝4*5＝20

How to solve one variable quadratic 3x square + 1 = 6x

3x^2+1=6x
3x^2-6x+1=0
It is solved by formula method
△=36-4*3*1=24
x=（6±√24)/(2*3)
=1±√6/3

Liberation distance 0.3 (3-x) = 0.9 (x + 5)

X=- 4.2727272727273