( 1)8 1; (2)25/64; (3)0.04; (4) 10? .

3. Find the square root of the following numbers:

( 1)49; (2)4/25; (3) 1/( 10∧6); (4)0.00 16;

6. What are the two nearest integers to the root number 40?

8. Find the value of x in the following formula:

( 1).x？ =25; (2).x？ -8 1=0; (3).25x？ =36。

9. The relationship between the height h (unit: m) of free fall and the falling time t (unit: s) is h=4.9t? Objects fall freely from buildings with a height of 120m. How long does it take to reach the ground (the result is rounded off)?

10. When the area of a square quadruples, how many times does its side length become? Expand the area to nine times the original? What about n times?

People's Education Edition, seventh grade, Volume II, Mathematics 103, page 2 and 3, question 1, rewrite the following equation into the form of expressing y with a formula containing x:

( 1)3/2x+2y = 1； (2) 1/4x+7/4y=2

(3)5x-3y=x+2y (4)2(3y-3)=6x+4

2. Solve the following equations by substitution method:

( 1){ y = x+3 7x+5y = 9(2){ 3s-t = 5 5s+2t = 15

(3){ 3x+4y = 16 5x-6y = 33(4){ 4(x-y- 1)= 3( 1-y)-2x/2+y/3 = 2

3. Solve the following equations by addition and subtraction:

( 1){ 3u+2t = 7 6u-2t = 1 1(2){ 2a+b = 3 3a+b = 4

(3){ 2x-5y =-3-4x+y =-3(4){ 1/2x-3/2y =- 1 2x+y = 3

Kneel down and beg for the title of page 7.8.9. 10 of seventh grade mathematics published by People's Education Edition, urgent! :pep../images/2004 10/pic _ 123358 . jpg

The topic is in this picture.

Ask for the answer to the sixth question on page 2 130 of the seventh grade mathematics textbook published by People's Education Press and the process of solving it. Thank you for setting x and y as the last one. I am in the seventh grade, too.

In-class 10 Minutes People's Education Edition, Volume II, answers pages 6, 7 and 8. Can you give me specific questions for me to see?

Begging for Education Edition, Grade 7, Volume II, Math Moving Point Problem 10, urgent need! People's Education Press has it online, just like a math book. :pep../czsx/jszx/qnxc/dzkb/

The problem of the second volume of seventh grade mathematics in People's Education Press is 1. The coordinate of point B on the Y axis and the length of the line segment to point A (0, -3) are 4, which is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

2. If the intersection point A (-2,5) is taken as the vertical line L of the X axis, the coordinate characteristics of the points on the straight line L are as follows.

3. It is known that point A (5+m, m-2) is on the X axis, then m = _ _ _ _ _ _ _ _ _ _, and the coordinates of point A are _ _ _ _ _ _ _ _ _.

4. If m>0, n<0, point Q( m, n) is in the fourth quadrant.

5. It is known that point P is in the fourth quadrant, the distance to the X axis is 2, and the distance to the Y axis is 3, so the coordinate of point P is _ _ _ _ _ _.

6. Move the point M(a, b) to the left by 2 unit lengths, and then move it down by 3 unit lengths, and its coordinates become (1, -6), then a=____, and b=____.

7. As shown in the figure, if Go is placed in a plane rectangular coordinate system, the coordinates of White Chess ② are (-7, -4) and White Chess ④ are (-6, -8), then the coordinates of Black Chess should be _ _ _ _ _ _.

8. As shown in the figure, it is known that the coordinates of village A and village B are (2, 1) and (6, 3) respectively, and a car starts from the origin O and travels to the right along the X axis. (1) When the car drives to point M (_ _ _ _ _ _), it is closest to Village A; (2) When the car drives to point N (_ _ _ _ _, _ _ _), it is closest to Village B; (3) When the car arrives at point P (_ _ _, _ _ _), it is as close as village A and village B. 。

9. As shown in Figure △ABC, the coordinates of each vertex are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _, and the area of this triangle is _ _ _ _ _ _.

10. As shown in the figure, the vertices of △ABC are all on the grid points of the square, and the coordinates of point A are (-1, 4). If △ABC is folded to the first quadrant along the Y axis, the coordinates of point C' corresponding to point C are.

1 1. If (7,8) is used to represent 8, 7, 7 and 8, it can be expressed as.

12. It is known that point P is in the second quadrant, and the sum of abscissa and ordinate is 1. Try to write a qualified point p.

13. In the plane rectangular coordinate system, the coordinates of point P (-5, -2) are obtained by translating it to the left by 2 unit lengths and then to the upward by 4 unit lengths.

14, the area of the triangle ABO surrounded by the coordinate origins o (0,0), a (-2,0) and b (-2,3) is _ _ _ _ _ _ _ _ _.

15, given the line segment MN=4 and MN∑y axis, if the coordinate of point M is (-1 2), the coordinate of point N is.

16, and arrange positive integers according to the law as shown in the figure. If the ordered number pair (n, m) is used to represent the nth row, and the m-th number from left to right, for example, (4,3) represents 9, then the number represented by (7,2) is _ _ _ _ _ _ _.

1.{x+y-z= 1 1 - 1

{y+z-x=5 - 2

{z+x-y= 1 - 3

1+2, get

2y= 16

y=8

1. Inequality system (x-2) (x-5)

Inequality (x-2) (x-5) < =0 Solution 2

The solution of inequality x(x-a)>=0

A>0, x>a or x < 0.

When a=0, the inequality x2 >；; =0 holds.

A<0, x>0 or x

So the inequality set (x-2) (x-5)

A> When =5, the inequality group has no solution and is an empty set.

2<= a<5, inequality group a.

A<2, inequality group 2

To sum up, inequality group (x-2) (x-5) < =0, x(x-a)>=0 and inequality (x-2) (x-5) < =0 have the same solution.

Then a < 2

2. Find the natural number solutions of inequality group 3 (x- 1)+2 < 5x+3, (x- 1)/2+x≥3x-4.

The solution of an inequality group is X & gt-2.

The solution of the second inequality group is X≤7/3.

sulphur dioxide

3. 1 if the solution set of inequality group x+a < b, x-a > b is -2 < x < 4, find the solution set of ax+b < 0.

X+A \u B，X—A \u B

So a+b

-2 & lt； X< iv

So a+b=-2.

b-a=4

Addition b= 1, a=b-4=-3.

ax+b & lt； 0

-3x+ 1 & lt； 0

3x & gt 1

x & gt 1/3

4. Equation 3X+2Y=M+ 1, 4X+3Y=M- 1. If X >: Y, find the value of m..

Writing process

3X+2Y=M+ 1 ( 1)

4X+3Y=M- 1 (2)

(2)*5-( 1)*7

20x+ 15y-2 1x- 14y = 5m-5-7m-7

-x+y=-2m- 12

x & gty

So y-x < 0.

-2m- 12 & lt； 0

2m & gt- 12

m & gt-6

2+3，get

2z=6

z=3

Substitute y = 8 and z = 3 into 3, and you get.

x=6

2.36 bricks, 36 people moved, 4 men and 3 women moved, and two children moved one. How many men, women and children are there?

Solution:

Let there be a man, a woman and a child. According to the meaning of the question, we can get the system of equations.

4a+3b+0.5c=36，

a+b+c=36。

Find the integer solution of this equation,

Eliminate c to get 7a+5b=36.

7a can only take 7, 14, 2 1, 28,

5b can only take 5, 10, 15, 20, 25,

Of these figures, only 2 1+ 15 = 36, and others are not.

At this time, a=3, b=3 and c=30.

There are 3 males, 3 females and 30 children.

3. 1 corner, 5 corner, 1 yuan 10 coin, and take out 15 coin from it. 7 yuan 1 jiao 5 jiao 1 yuan how many coins do you take?

If 1, 5 and 1 yuan coins are x, y, Z Y and z respectively, there are:

X+Y+Z= 15 A

0. 1X+0.5Y+Z=7 B

And 0

From equation a, x =15-y-z d.

Replace b with d,

0. 1( 15-Y-Z)+0.5Y+Z = 7

Simplification: Y= 1/4(55-9Z) E

Because y is an integer, from e, z can only be: z=3.

Substituting z=3 into e, you can get: Y=7,

Substitute z = 3 and y = 7 into a, and you can get X=5.

That is, 1 corner, 5 corner and 1 yuan take 5, 7 and 3 pieces respectively.

4. 65 1 junior high school students in a school. Senior two is more than senior three 10%, and senior one is more than senior two by 5%. How many people are there in each of the three grades?

Solution:

Grade one: X Grade two: Y Grade three: Z.

x+y+z = 65 1y = 1. 1z x = 1.05y

Answer: x=23 1 y=220 z=200.

5、x+y= 10

2x-3y+2z=5 - (2)

x+2y-z=3 - (3)

(3)*2+(2)

4x+y= 1 1 - (4)

(4)-( 1)

3x= 1

x= 1/3

Substituting x= 1/3 into (1), the result is

y=29/3

Substitute x= 1/3 and y=29/3 into (3) to get the result.

z=50/3

Xiaoming went to see his grandmother at the weekend. He bought apples, pears and bananas in the supermarket with 74 yuan money. It is known that apple 5 yuan/kg, pear 5.5 yuan/kg, banana 4 yuan/kg, three kinds of fruits * * * bought 15.5 kg, and apple bought 2 kg more than pear. How many kilograms of apples, pears and bananas did you buy?

Let the weights of apples, pears and bananas be x, y and z respectively.

5x+5.5y+4z=74

x+y+z= 15.5

x-y=2

Solution: x=6 y=4 z=5.5

7. There are three commodities, A, B and C. If you buy five A's, two B's and four C's, you need 80 yuan. It takes 144 yuan to buy 3 A's, 6 B's and 4 C's. Q: It takes _ _ _ _ yuan to buy A's, B's and C's.

If the unit prices of the three commodities are X, Y, Z, Y and Z respectively, then:

5x+2y+4z=80

3x+6y+4z= 144

Two formulas have been added:

8x+8y+8z=224

x+y+z=28

Party A, Party B and Party C need 28 yuan to purchase 1 piece respectively.

8、x-2y=-9

y-z=3

2z+x=47

x-2y=-9……( 1)

y-z=3……(2)

2z+x=47 ……(3)

(3)-( 1)

2z+2y=56

z+y=28……(4)

(4)+(2)

2y=3 1

y=3 1/2

Bring y=3 1/2 into (4)

z+(3 1/2)=28

z=25/2

Bring z=25/2 into (3)

25+x=47

x=22

x=22，y=3 1/2，z=25/2

9、X+2Y+Z= 10

2X+3Y-Z=3

3X+2Y+2Z= 17

Solution:

(1)+(2) Available:

3X+5Y= 13 (4)

(2)*2+(3) Available:

7x+8Y=23 (5)

(4)*7-(5)*3:

1 1Y=22

Y=2

Bring Y=2 into (4).

X= 1

Bring x = 1 and y = 2 into (1).

Z=5

therefore

X= 1

Y=2

Z=5

10, the sum of a, b and c is 4 1. The number A is twice the number C times 3, and the ratio of A to B is 3:2. Find these three numbers.

Set an x b y c z,

x+y+z=4 1 ①

2x=3z+3 ②

x/y=3/2 ③

Substitute y=2x/3 in ③ into 5x/3+z=4 1 ④ in ①.

② Solve x =18z =11y =12 simultaneously.

1. The relationship between the three sides of the triangle is A+B >; c，a-b & lt； C. The two sides are 4 and 7 respectively, and the third side is between 3~ 1 1. The circumference is odd and the third side may be 4, 6, 8, 10.

2. If the pharmaceutical factory is 3x, the perimeter is 3x+3x+4x=20, x=2, the pharmaceutical factory is 6, and the ground becomes 8.

3. For example, drawing shows that the waist length is different from the bottom length by 3, and the topic is divided into two situations: regular and bottom length.

1) waist circumference

Let the waist length be a, the base length be a-3 and the midline length be b, and according to the midline theorem

a^2+(a-3)^2=2(0.5a)^2+2*b^2

a-3 + 0.5a +b= 12

Solution: Get:

2) Compensation

According to the midline theorem, let the waist length be a, the bottom length be a+3, and the midline length be b.

a^2+(a+3)^2=2(0.5a)^2+2*b^2

a + 0.5a +b= 12

Solution: Get:

Calculate the detailed results yourself.

4. The other two sides may be: 1, 52, 42, 53, 33, 43, 54, 4, 55, 5 * * 8.

5. All terms in the equation are not less than 0, a = 3, b = 4 and c = 3. So it is an isosceles triangle.

6, 1) One must be 5, the other must be 5, and the radix is 16-5-5=6.

2) One side is 5. If this side is waist, the same as above. If it is bottom, the waist length is (16-5)/ 2=5.5.

All the answers are given to you. Don't forget to adopt them when you're done. O(∩_∩)O hahaha ~O(∩_∩)O hahaha ~O(∩_∩)O hahaha ~

People's Education Edition (4560) Re-examines the seventh grade in class. I am Wang Nan, 1 a middle school student. I have a good friend, Jim. He is an American girl. We are all in Class Two, Grade Eight. She 15 years old, one year older than me. We all study hard. I am good at physics, but she is good at math. We often help each other with our lessons. We both like to help others. We both like sports very much. Jim likes playing basketball. But I like playing stud. She likes green, but I like red. Although we have different ways, we are good friends.

What is the answer to the second question on page 102 of the second volume of mathematics in the seventh grade of People's Education Edition? Solution: the speed of the ship in still water is x km/h, and the current speed is y km/h, then according to the meaning of the question:

x+y=20，…①

x-y= 16。 ……②

From ①+②: 2x=36, the solution is x= 18. Bring x= 18 into ①: y=2.

The solution of the equation is: x= 18,

y=2。

Answer: The speed of the ship in still water is18km/h, and the current speed is 2km/h. 。

People's Education Edition has almost learned the second volume of the seventh grade math class, but if you really want it, you can go to the bookstore and buy one, and the money is not much. Just take out the answers inside and copy them, hehe. . I wish the teacher not to confiscate your answers when you are in the eighth grade (and bless me).