How to raise the common factor of the square of X (x + y) (X-Y) - x (x + y)

How to raise the common factor of the square of X (x + y) (X-Y) - x (x + y)

x(x+y)(x-y)-x(x+y)²
=x(x+y)[(x-y)-(x+y)]
=x(x+y)(x-y-x-y)
=-2xy(x+y)

The quadratic power of (x + y + Z) and the quadratic power of (X-Y-Z)

The power of (x + y + Z) - (X-Y-Z)
=(x+y+z-x+y+z)(x+y+z+x-y-z)
=(2y+2z)*2x
=4x(y+z)

The answer to the article "heart window"
1. After listening to the old lady's description, what kind of beautiful scenery will emerge in your mind?
2. Talk about the meaning of "heart window".
How do you feel?

Don't the little girl want to see the scenery outside the window?
2. The snow is falling down, as if covering the whole world. On the roof, the streets are covered with thick white feather coats. Outside the window, there is a tall pine. The naughty snow elf puts on a white velvet hat for it. The disobedient kitten is also curious about the white world, and runs out from the white "carpet" hiding from the cat mother, Soft small feet to the earth printed on a lovely plum blossom
3. The little girl is undoubtedly lively and naive. She also likes snowy days. But she can only lie in bed and can't move. She can't even see the scenery outside the window. The ward is lonely and boring. The physical pain and mental distress bring the little girl double torture. She is full of expectation and asks her grandmother about the snowy scenery outside the window, If the old woman told her that there was a wall outside the window, it would be a heavy blow to the little girl. The white lies of the old woman gave the little girl the space to imagine and the courage and strength to fight against the pain. She spent the most depressed and helpless time with the little girl. In the little girl's heart, she sowed a seed of kindness. So although her eyes didn't see it, But the window opened in the little girl's heart

How do teachers preview the fourth grade texts?

Mark pinyin on the textbook first so as to read the text aloud
Then new words are made into words
Escape: escape, exile, death
Calamity: calamity, calamity never comes alone, calamity comes from heaven
Precepts: lessons, precepts, family precepts
Average: even, average
Uniform: uniform, uniform speed
Province: save, save, Hebei Province
Some: some, someone, Zhang
Candid: flat, candid, candid
The next step is to understand the meaning of some words
Enlightenment: the principle of enlightenment
More than: use rhetorical tone to indicate beyond a certain number or range
Wing: a wing shaped component mounted on both sides of the fuselage to provide lift
Finally, I'll give you the key and difficult points
1. Know the word "whale" and write all the new words. Understand the words of tremble, key, lesson, ease, resistance, etc
2. Read the text correctly, fluently and emotionally
3. Be able to tell the content of three, four and five natural paragraphs (key points)
4. Understand why human beings call all kinds of creatures in nature "teachers" and cultivate their interest in scientific research. (difficult)

Solving the equation 4x-3 (20-x) = 3

4x-60+3x=3
4x+3x=3+60
7x=63
x=9
I don't know if you will move items

0.73 * 99 (simple calculation)

0.73×99=0.73×﹙100－1﹚=73－0.73=72.27

A primary school on the knowledge of the circle of mathematical fill in the blanks
Wang Hong uses a 10.28cm rope to form a semicircle with a radius of () m and an area of () m2
If you answer, please explain why,

Let the radius of semicircle be x cm
Then: 2x * 3.14 = 10.28 * 2-4x
6.28X=20.56-4X
10.28X=20.56
X=2
So:
The semicircle area is (2 * 2 * 3.14) divided by 2 = 6.28 square centimeters

How much is the original price? 2. A bucket of water is poured out 40% for the first time, 12 liters for the second time, and 30 liters for the second time. How many liters is left?

Let the original price be x, then we can get the formula: X (1-20%) (1-20%) = 144, the solution is: x = 225 yuan, that is, the original price is 225 yuan
(2) From the beginning to the end of the 40% calculation:
30-12 = 18 liters
Original water volume in the bucket:
18 / 0.4 = 45 liters
What's left in the bucket
45-30=15

If f (x) = x + ln [g (x) x ^ 2] is an odd function, then G (x) can only be

This can be seen layer by layer
First of all, only odd function + odd function = odd function
Y = x is an odd function, so ln [g (x) x ^ 2] is also an odd function
Because the domain of y = ln (x) is no longer symmetric about the Y axis, its value must always be 0
So g (x) x ^ 2 must be 1
So g (x) = 1 / (x ^ 2) (x ≠ 0)

As shown in the figure, the north-south Beijing Road and the East-West Kashi road in an urban area intersect at point O. a goes from west to east at the speed of 4m / s along Kashi Road, and B goes from south to North at the speed of 3m / s along Beijing road. When B goes to 50m North of point O, a just arrives at point O. if two people continue to walk forward, find their respective positions when they are 85m apart

Suppose that after x seconds, the distance between two people is 85m. According to the meaning of the question, we get (4x) 2 + (50 + 3x) 2 = 852, remove the brackets to get 25x2 + 300X = 4725, that is, 25x2 + 300x-4725 = 0, simplify to get x2 + 12x-189 = 0, and (X-9) (x + 21) = 0, and get X1 = 9, X2 = - 21 (not in line with the actual situation, rounding off). When x = 9, 4x = 36, 50 + 3x = 77 So when they are 85 meters apart, a is 36 meters east of O and B is 77 meters north of O