How to calculate 25 (x-1) 2 = 16 (x + 2) 2

25 (x-1) 2 = 16 (x + 2) 2 | (x-1) / (x + 2) | = 4 / 5 (x-1) / (x + 2) = ± 4 / 5, 1-3 / (x + 2) = ± 4 / 5, 3 / (x + 2) = 1 ± 4 / 5, 3 / (x + 2) = 9 / 5 or 1 / 5, x = - 1 / 3 or 13

A computing device, after inputting x, outputs y. The following result is x 124 9 16 25 36 y 123 4 56 7
Q: 1. The output is 100, what is the output?
2. What is the relationship between Y and X?
3. After inputting a certain number, the calculation device will display "error cannot be calculated". What do you think is the reason?

(1) input, input is 100, output is 10;
﹙2﹚Y＝√X;
(3) the reason is: the input number is negative

Let f (x) = x ^ - | x |, if f (log3 (M + 1))

Function f (x) = x ^ (- |x|), x > 0,
∴f(x)=x^(-x)=e^(-xlnx),
f'(x)=x^(-x)*(-lnx-1),
09,
m>8.

The original price of a kind of beverage is 4 yuan per bottle. When you buy four for one free in the supermarket, you have to buy 10 bottles. How much does it cost? How much is the discount

Equivalent to 10-2 = 8 bottles, 8 * 4 = 32 yuan, 8 △ 10 = 0.8 = 80%

New concept English is better or new concept English Youth Edition is better, how to learn?
I am 12 years old, ready to see "new concept English 1", but not read the youth version better?
How to learn new concepts?
Is it better to learn from the original version or the youth version?

There is nothing good or bad. As long as you study hard, any book is good
The most recommended learning methods: 1. Listen until you are proficient (you don't need to understand). For example, you can concentrate on listening to it 100 times. 2. Learn, open a book, learn the words you don't understand, and look them up in a dictionary until you understand the meaning of each word and sentence. 3. Read and imitate the voice, intonation and tone of the recording you just listened to, For example, if you read it 100 times, it can be called catchy. 4. Retell, retell in your own words, say it out, no matter what you say is right or wrong, just say it until you are satisfied
The above learning method is very good, but the disadvantage is that the feeling of progress is not linear, but step like, that is to say, you feel that your progress is very limited after 3 months of study, but suddenly you feel that you have leaped a step, that day that feeling is very good, but before that 3 months you will feel very depressed, it is easy to let you down, And we should firmly believe that this method is effective
Another method is recommended, but the English learned by this method is not as flexible as the above method, but the advantage is that you can see the learning effect, make progress every day, have a sense of achievement, and are not easy to lose heart. The learning method is: recite, first of all, when you understand the text, try to imitate the voice, intonation and tone of the recording to recite, until recitation, of course, the more familiar the better
Study hard. You are only in the first grade of junior high school. No matter which method you follow, as long as you stick to it, when you graduate from junior high school, you will finish learning new concept 2, and when you graduate from senior high school, you will learn new concept 4. You will be very good. At least CET-4 will be easy
Pay attention, don't rush the progress, you know, this is your own to learn new concepts, no one forced you to learn a few lessons a day, you have to learn solidly, learn that they think this lesson is really nothing to learn, learn the next lesson, use spare time to learn a lesson a week, you will learn very well, learn anything is expensive, remember

A. B is 80 kilometers apart. A truck starts from a and goes to B. two hours later, it drives a car from a in the same direction. The speed of the car is three times that of the truck. As a result, the car arrives at B 40 minutes earlier than the truck and the speed of the two cars is faster

40 minutes is equal to two-thirds of an hour. The equation is 80 divided by 3x and two-thirds is equal to (80 minus 2x) divided by X. the solution is truck speed 20 and car speed 60

Given that a is a root of the equation x ^ 2-x-1 = 0 about X, find the values of the following formulas. [1] A-1 / A. [2] 2006-a ^ 3 + 2A^
How to solve it

a^2-a-1=0
[1] 1
[2] The title is not detailed

A. B is 950 meters away from the two places, and a and B set out from a for half an hour at the same time. Then how many times does a and B meet nearest to B?
A walk, 40 meters per minute, B run, 150 meters per minute

The meeting here means meeting face to face, or catching up?
The following solution only considers head-on encounter
Half an hour, Party A and Party B are:
(40 + 150) * 30 = 5700m
Equivalent to 5700 / 950 = 6 whole courses
The speed ratio is 40:150 = 4:15
Every time they meet, the distance between them is two whole journey,
Among them, the first line 4 / (4 + 15) * 2 = 8 / 19
In half an hour, Party A and Party B meet at most 6 / 2 = 3 times
1) For the first meeting point, the distance b is 1-8 / 19 = 11 / 19
2) For the second meeting, a's journey: 4 * 8 / 19 = 32 / 19,
32 / 19-1 = 13 / 19 from B
3) The third meeting, a driving: 6 * 8 / 19 = 48 / 19 whole journey,
3-48 / 19 = 9 / 19 from B
So when Party A and Party B meet for the third time, they are closest to B

Test whether the numbers listed in brackets after the following equation are the solutions of this equation: 2 (x + 2) - 5 (1-2x) = - 13, {x = - 1,1
Test whether the numbers listed in brackets after the following equation are the solutions of the equation:
2（x+2）-5(1-2x)=-13,{x=-1,1}
To substitute x = - 1 into the two sides of the equation: left=___ =_ , right= Because on the left_ So x = - 1 is the solution of the equation
Substituting x = 1 into both sides of the equation yields: left=__ =_ , right=_ Because the left side is not equal to the right side, so___ .

2 (x + 2) - 5 (1-2x) = - 13, {x = - 1,1} substituting x = - 1 into both sides of the equation
Left = 2 (- 1 + 2) - 5 [1-2 × (- 1)] = - 13
Right = - 13
Because left = right,
So x = - 1 is the solution of the equation
Substituting x = 1 into both sides of the equation
Left = 2 (1 + 2) - 5 (1-2 × 1) = 11
Right = - 13, because left ≠ right,
So x = 1 is not the solution of the equation

Let's help. Party A and Party B are going from west to east along a highway. The speed is 3000 meters per hour and 5 kilometers per hour respectively. Party A leaves a at 12 noon
How far is it from a when B overtakes a?

Let B catch up with a in X hours after departure
3*2+3x=5x
The solution is: x = 3
3 * 5 = 15 km
A: it's 15 kilometers away from a

How to calculate 25 (x-1) 2 = 16 (x + 2) 2