How to compare the size of rational numbers on the number axis

How to compare the size of rational numbers on the number axis

Just remember one:
On the number axis, the number on the right is always larger than that on the left

Can all rational numbers be compared by number axis? Why?

Yes, centered on the origin, the positive direction is on the right, and the more right the number is, the larger the number is

What is the basis for comparing the size of rational numbers on the number axis?

The right is always bigger than the left

Binary linear equations 70, the number is not too large, simple, to calculate the problem, do not apply the problem, urgent!

1) 66x+17y=3967
25x+y=1200
Answer: x = 48, y = 47
(2) 18x+23y=2303
74x-y=1998
Answer: x = 27, y = 79
(3) 44x+90y=7796
44x+y=3476
Answer: x = 79, y = 48
(4) 76x-66y=4082
30x-y=2940
Answer: x = 98, y = 51
(5) 67x+54y=8546
71x-y=5680
Answer: x = 80, y = 59
(6) 42x-95y=-1410
21x-y=1575
Answer: x = 75, y = 48
(7) 47x-40y=853
34x-y=2006
Answer: x = 59, y = 48
(8) 19x-32y=-1786
75x+y=4950
Answer: x = 66, y = 95
(9) 97x+24y=7202
58x-y=2900
Answer: x = 50, y = 98
(10) 42x+85y=6362
63x-y=1638
Answer: x = 26, y = 62
(11) 85x-92y=-2518
27x-y=486
Answer: x = 18, y = 44
(12) 79x+40y=2419
56x-y=1176
Answer: x = 21, y = 19
(13) 80x-87y=2156
22x-y=880
Answer: x = 40, y = 12
(14) 32x+62y=5134
57x+y=2850
Answer: x = 50, y = 57
(15) 83x-49y=82
59x+y=2183
Answer: x = 37, y = 61
(16) 91x+70y=5845
95x-y=4275
Answer: x = 45, y = 25
(17) 29x+44y=5281
88x-y=3608
Answer: x = 41, y = 93
(18) 25x-95y=-4355
40x-y=2000
Answer: x = 50, y = 59
(19) 54x+68y=3284
78x+y=1404
Answer: x = 18, y = 34
(20) 70x+13y=3520
52x+y=2132
Answer: x = 41, y = 50
(21) 48x-54y=-3186
24x+y=1080
Answer: x = 45, y = 99
(22) 36x+77y=7619
47x-y=799
Answer: x = 17, y = 91
(23) 13x-42y=-2717
31x-y=1333
Answer: x = 43, y = 78
(24) 28x+28y=3332
52x-y=4628
Answer: x = 89, y = 30
(25) 62x-98y=-2564
46x-y=2024
Answer: x = 44, y = 54
(26) 79x-76y=-4388
26x-y=832
Answer: x = 32, y = 91
(27) 63x-40y=-821
42x-y=546
Answer: x = 13, y = 41
(28) 69x-96y=-1209
42x+y=3822
Answer: x = 91, y = 78
(29) 85x+67y=7338
11x+y=308
Answer: x = 28, y = 74
(30) 78x+74y=12928
14x+y=1218
Answer: x = 87, y = 83
1、 Multiple choice questions:
1. Among the following equations, the one that is a quadratic equation of two variables is ()
A．3x－2y=4z B．6xy+9=0 C． +4y=6 D．4x=
2. Among the following equations, the one that is binary linear equation is ()
A．
3. Quadratic equation 5a-11b = 21 ()
A. There are only one solution B. There are countless solutions C. There are no solutions d. There are only two solutions
4. The common solution of the equation y = 1-x and 3x + 2Y = 5 is ()
A．
5. If X-2 + (3Y + 2) 2 = 0, then the value of is ()
A．－1 B．－2 C．－3 D．
6. If the solutions of the equations are equal to the values of X and y, then K is equal to ()
7. In the following formulas, the number of quadratic equations of two variables is ()
①xy+2x－y=7； ②4x+1=x－y； ③ +y=5； ④x=y； ⑤x2－y2=2
⑥6x－2y ⑦x+y+z=1 ⑧y（y－1）=2y2－y2+x
A．1 B．2 C．3 D．4
8. There are 246 students in a certain grade, among them, the number of boys y is 2 times less than that of girls X. then ()
A．
2、 Fill in the blanks
9. Given the equation 2x + 3y-4 = 0, expressed by the algebraic formula containing x, y is: y=_______ X is expressed as: X by an algebraic expression containing y=________ ．
10. In the bivariate linear equation - x + 3Y = 2, when x = 4, y=_______ When y = - 1, X=______ ．
11. If x 3m-3-2yn-1 = 5 is a quadratic equation of two variables, then M=_____ ,n=______ ．
12. Given the solution of the equation x-ky = 1, then K=_______ ．
13. It is known that X-1 + (2Y + 1) 2 = 0 and 2x KY = 4, then K=_____ ．
14. The positive integer solutions of bivariate linear equation x + y = 5 have______________ ．
15. Consider a quadratic equation of two variables to be_________ ．
16. If the solution is known, then M=_______ ,n=______ ．
3、 Answer questions
17. When y = - 3, the bivariate linear equation 3x + 5Y = - 3 and 3y-2ax = a + 2 (the equation about X, y) have the same solution, and the value of a is obtained
18. If (A-2) x + (B + 1) y = 13 is a quadratic equation with respect to x, y, then what conditions do a and B satisfy?
19. The values of solutions X and y of binary linear equations are equal, and K
20. Given that X and y are rational numbers and (│ x │ - 1) 2 + (2Y + 1) 2 = 0, what is the value of X-Y?
21. Given the equation x + 3Y = 5, please write out a quadratic equation of two variables so that the solution of the system of equations composed of it and the known equation is
22
(1) Mingming went to the post office to buy 13 stamps of 0.8 yuan and 2 yuan, which cost 20 yuan in total. How many stamps did Mingming buy?
(2) Put several chickens into several cages. If there are four chickens in each cage, there is one chicken without cage. If there are five chickens in each cage, there is one cage without chicken. How many chickens and how many cages are there?
23. Do the solutions of the equations satisfy 2x-y = 8? Are the values of a pair of X and Y satisfying 2x-y = 8 the solutions of the equations?
Is there an integer m so that the equation 2x + 9 = 2 - (m-2) x has a solution in the range of integers? Can you find several values of M? Can you find the corresponding solution of X?
answer:
1、 Multiple choice questions
1. D analysis: master the three necessary conditions for judging binary linear equation: ① contain two unknowns; ② the degree of the term containing unknowns is 1; ③ both sides of the equation are integers
2. A analysis: there are three necessary conditions for binary linear equations: ① there are two unknowns; ② the degree of each term containing unknowns is 1; ③ each equation is an integral equation
3. B analysis: without restriction, a binary equation of first degree has innumerable solutions
4. C analysis: using exclusion method, one by one into the verification
5. C analysis: use the properties of non negative numbers
6．B
7. C analysis: according to the definition of bivariate linear equation, the integral equation with two unknowns and the number of unknowns is not more than once is called bivariate linear equation. Pay attention to the arrangement of the equation
8．B
2、 Fill in the blanks
9． 10． －10
Let 3m-3 = 1, n-1 = 1, M =, n = 2
12. - 1 Analysis: by substituting the equation x-ky = 1, we can get - 2-3K = 1, х k = - 1
13.4 analysis: X-1 = 0, 2Y + 1 = 0,
We substitute x = 1, y = -, 2 + k = 4, 2 + k = 1
14．
Analysis: ∵ x + y = 5, ∵ y = 5-x, and ∵ x, y are positive integers,
When x = 1, y = 4; when x = 2, y = 3; when x = 1, y = 3; when x = 2, y = 4; when x = 2, y = 3; when x = 2, y = 4; when x = 2, y = 3; when x = 2, y = 3; when x = 2, y = 3, y;
When x = 3, y = 2; when x = 4, y = 1
The positive integer solution of X + y = 5 is
15. X + y = 12 analysis: set up the equation according to the quantitative relationship between X and y, such as 2x + y = 17, 2x-y = 3, etc,
The answer to this question is not unique
16.14 analysis: solve the problem in
3、 Answer questions
17. ∵ y = - 3, 3x + 5Y = - 3, ∵ 3x + 5 × (- 3) = - 3, ∵ x = 4,
The equation 3x + 5Y = --- 3 and 3x-2ax = a + 2 have the same solution,
∴3×（－3）－2a×4=a+2,∴a=－ ．
18. (A-2) x + (B + 1) y = 13 is a bivariate linear equation about X, y,
∴a－2≠0,b+1≠0,∴a≠2,b≠－1
Analysis: in this problem, if there are two unknowns, the coefficient of the unknowns should not be 0
(if the coefficient is 0, then the term is 0)
19. From the meaning of the title, it can be seen that x = y, 4x + 3Y = 7 can be changed into 4x + 3x = 7,
We substitute x = 1, y = 1 into KX + (k-1) y = 3 to get K + k-1 = 3,
By the special relationship between two unknowns, one unknowns can be replaced by an algebraic formula containing another unknowns, and the value of two unknowns can be obtained by changing "two variables" into "one variable"
20. From (│ x │ - 1) 2 + (2Y + 1) 2 = 0, we can get │ x │ - 1 = 0 and 2Y + 1 = 0, ｜ x = ± 1, y = -
When x = 1, y = - X-Y = 1 + =;
When x = - 1, y = - X-Y = - 1 + = -
Analysis: the square of any rational number is non negative, and the sum of two non negative numbers in the question is 0,
Then the two nonnegative numbers (│ x │ - 1) 2 and (2Y + 1) 2 are all equal to 0, thus │ x │ - 1 = 0, 2Y + 1 = 0
21. Experience is the solution of the equation x + 3Y = 5. Write another equation, such as X-Y = 3
(1) set X stamps for 0.8 yuan and Y stamps for 2 yuan
(2) There are x chickens and Y cages
23. Satisfaction, not necessarily
Analysis: the solution of ∵ is not only the solution of the equation x + y = 25, but also satisfies 2x - y = 8
The solution of the system of equations must satisfy any one of them, but the solution of equation 2x-y = 8 has no array,
If x = 10, y = 12, it does not satisfy the equations
The original equation can be transformed into - MX = 7,
When m = 1, x = - 7; when m = - 1, x = 7; when m = 7, x = - 1; when m = - 7, x = 1

If the length of a rectangle is reduced by 4 meters and the width is reduced by 2 meters, the area will be reduced by 44 square meters, and the remaining part is just a square. The perimeter of the square is______ Rice

As shown in the figure, let the side length of this square be x, 4x + (x + 4) × 2 = 44 & nbsp; & nbsp; & nbsp; 4x + 2x + 8 = 44, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 6x = 36, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 6 square

How much is 72 times 74 out of 75?

72×74/75
=72×(1-1/75)
=72×1-72×1/75
=72-72/75
=71 1 / 25

Practice and test the answers of p85-86 and multiple choice questions in the first day of junior high school. Otherwise, turn off at 8:15
Practice and test the answers of p85-86 and multiple-choice questions in the next semester. Or turn it off at a quarter past eight

654

What is 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9. + 1000?

It's 500, 500
Use (first item + last item) * number of items / 2
That is, (1 + 1000) * 1000 / 2 = 500500
This kind of continuous addition can use this formula

1, 3, 6 and 8 are equal to 24
Who knows?

(8-3-1)*6=24

English translation
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This is about the content, try to use some low-level words

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,"Robinson Crusoe".I think it is a
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to be personally on the scene.The
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ability.He can survive in the harsh
environment,and take good care of
himself.The most important thing is
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gives in the nature.This is the first
book I read,it made me know how to
have a hope of life to live,and our
living environment is so good.Do not
bow to difficulties,try to be a brave
man..