Junior high school math questions are answered by well wishers, and I hope it will be soon.

5. Simplify: 1, (x +1) (x +1) (x 1) (x +1) (x 1).

x to the fourth power 1

2、（2a+1/2)(2a－1/2)(4a²+1/4)(4a²－1/4)(4a²+1/4)

16a to the fourth power 1 16

3、(x+3)(x－3)－2(2－x)(2+x)(x²－9)－2(4－x²)

x²－9－8+x²

2x²－17

4、(2x+3y)(3x－2y)－(x－2y)(x＋2y)(6x²+5xy－6y²)－x²－4y²)5x²+5xy－2y²

5, (a 4) (a 5) + (3a + 5) (3a 5) a to the fourth power 9a + 20 + (9a 25) a to the fourth power 5

6、[(2a－1)(2a+1)+(a+2)(a－2)－4a²](a²+5)

4a²－1)+(a²－4)－4a²](a²+5)(a²－5)(a²+5)

A to the fourth power 25

1) (a+2b－3)（a+2b+3)

a+2b)²－3²]

a²+4ab+4b²－9

2) （x²+x+3)(x²－x－3）

x²+x+3)[－x²+x+3）]

(x+3)+x²][x+3)－x²]

(x+3)²－x²]

x²+6x+9－x²）

6x－93） （x+2y+3）²－x－2y+3）（x－2y－3）（x+2y+3）²－x－2y）+3】【（x－2y）－3】（x+2y+3）²－x－2y）²－3²】

x²+4y²+4xy+12y+6x+9）－（x²+4y²－4xy－9）

8xy+12y+6x+18

7 (1) original formula = (100 - square = 100 square - 2 times 100 times square = 10000 - 40+

2) In the same way, the square of the original formula = (2000 + 5) = 40200258 square of the original formula = (a + 2b) - 9 = the square of a + 4ab + 4b2 - 9, and the other questions are basically this idea.

Question 8 (1) :(a+2b) squared - 9 = a square + 4ab + b squared - 9

Question 8 (2) x to the fourth power - (x+3) squared = x to the fourth power - x squared - 6x-9

Question 5 (1) (x 2+1) (x+1) (x-1) = (x 2+1) (x 2-1) = x 4-1 Calculate first (x+1) (x-1) according to the squared difference formula.

Question 5 (2) Original formula = ((2a) 2-(1 2) 2) (4a 2+1 4) = (4a 2-1 4)(4a 2+1 4) = 16a 2-1 16

Same as above The same is true for sub-questions 3 4 5 of question 5, according to the formula of square difference (a+b)(a-b)=a2-b 2

2 is squared, e.g. x 2 is the square of x).

After 1 6 hours at a speed of 4 km h, a total of 4 * 1 6 = 2 3 km was covered

There are still 30 - 2 3 = 88 3 km left, which needs to be reached in 2 3 hours, so the car speed x needs to be met.

88/3) / x <= 2/3

The solution is x > = 44 km h

The total columnar formula is:

30 - 4 * 10/60)] / x <= 40/60

Buses travel at least X kilometers per hour on average.

Then: 4*10 60+x*40 60=304x=176

Solution x=44

Then the average bus travels at least 44 kilometers per hour.

Rely on the mountains and mountains, and rely on everyone to fall. It's better to be on your own

Go back and flip through the book and you'll understand. Others can only help you now, what do you do with the exam.

Sixth.

Set the wind speed x km h

then (552+x)*

The solution is x=24

So 576 downwind, 528 upwind

Distance 576*

Application: Let the distance be s kilometers and the wind speed be v kilometers per hour.

s/(552+v)=

s/(552-v)=6

The solution is s=3168

v=24 So the aircraft has a downwind speed of 576 km h, a headwind speed of 528 km h, and the distance between the two cities is 3168 km.

6 hours.

h3. Set the wind speed to x kilometers per hour.

then there is: (552+x)*

The solution is x=24

The distance between the two cities is (552-24)*6=3168 km.

3 out of 1The speed downwind is 576km, the headwind is 528km, and the distance is 3168km

- (3x-7)

4x+8=7-3x

7x=-1x= - 1/7)

2.Let the number in the tenth digit be x and the single digit be x+4

This two-digit number is 10x+(4+x).

According to the question: 2x+4=(1 4)(10x+x+4), the solution: x=4

This two-digit number is 48

3.(1)(-2) 3 (again 3 8+2 again 1 3) 24= [-8*(-1 16)] 16+(11 4-11 8+7 3)*24

1.is the opposite of each other, i.e., there is 4x+8=-(3x-7) to get x=-1 7

Let the square be x and the circle be y, and the title will have:

xy=36x-y=2

y=-1 + root number 37 or y=-1 - root number 37

x = 1 + root number 37 or x = 1 - root number 37

224 divided by a triangle equals a square minus a circle.

So 224 triangle = 2 triangle = 112, so the square is 1 + root number 37, the circle is -1 + root number 37, the triangle is 112 or the square is 1 - root number 37, the circle is -1 - root number 37, and the triangle number is 112

As upstairs, the square is x. The circle is y. The triangle is z-circle multiplied by the square equals 36, and the square minus the circle equals 2. Two equations can be listed: xy=36

x-y=2 is solved, x=1 + root number 37 y=-1 + root number 37224 minus triangle is equal to square minus circle.

224-z=x-y=2, so z=222, pure call it off, and the watchtower owner adopts.

Solution: Let the square be x. The circle is y. The triangle is z

Column two equations.

xy=36x-y=2

In the solution, x = root number 37 + 1 y = root number 37-1224 divided by triangle equals square minus circle.

224/z=x-y=2，∴z=112

Let the square be x, the circle y, and the triangle z

x+y=36

x-y=2224÷z=x-y

x=19y=17

z=112Answer: 19 for a square, 17 for a circle, and 112 for a triangle

The triangle is 112, the square is 72 35, and the circle is 2 35 I also have a phone.

Let the square be x, then the circle is x-2x(x-2)=36 to solve it, it's hard to call, my phone.

A junior high school math problem.

Hello answer choose c

The analysis is as follows. Use the induction formula.

If it helps, please adopt it in time o( o Thank you.

The area of the rectangle is 6 square centimeters, with one side being x centimeters and the other side being y centimeters.

Find the functional relation of y to x, and write the range of values of the independent variable x.

y＝6/x.x belongs to 0 to 6

It's an inverse proportional function, which you'll always draw.

1）y=6/x (x>0)

2) Inverse proportional function image, keep the first quadrant, label units, etc.