(X-2) &# 178; = 9x & # 178; solve the equation

(X-2) &# 178; = 9x & # 178; solve the equation

The term is shifted and solved by the square difference formula

Given √ x + 1 / √ x = 3, find [√ X & # 178; + (1 / X & # 178;) + 21]

It seems that it should be √ [x & # 178; + (1 / X & # 178;) + 21]. If it is, it is better to do it: if you know the square of both sides: x + 2 + 1 / x = 9: x + 1 / x = 7, then the square of both sides: x ^ 2 + 2 + 1 / x ^ 2 = 49  x ^ 2 + 1 / x ^ 2 = 47  the formula is √ (47 + 21) = √ 68 = 2 √ 17

(x²+9x+20)÷(x+4)

Original form=
=(x²＋9x＋20)÷(x＋4)
=[(x＋4)(x＋5)]÷(x＋4)
=x＋5

It is known that the x power of 2 is equal to 3, the Y power of 2 is equal to 6, and the Z power of 2 is not equal to 1?

Let 2 ^ x = 3 ^ y = 6 ^ z = K
So x = log2, K
1/x=logk,2
Similarly, y = log3, K
1/y=logk,3
z=log6,k
1/z=logk,6
So 1 / x + 1 / y = logK, 2 + logK, 3 = logK, 6 = 1 / Z
So 1 / x + 1 / y = 1 / Z
If you don't understand,

Huanhuan read a story book. On the first day, she read 13 pages of the whole book, on the second day, she read 20 pages, on the third day, she read the remaining 14 pages, and on the third day, she left 38 pages of the whole book? (2) How many pages are left to read?

(1) Suppose there are x pages in this book, from the meaning of the title: (x-13x-20) × (1-14) = 38x, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; (23x-20) × 34 = 38x, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp

-The square of 2A (one-half of AB's square + B's Square) - the square of 5ab (two-fifth of a's square-a)

-The square of 2A (one-half of AB's square + B's Square) - the square of 5ab (two-fifth of a's square-a)
=-a^3b^2+2a^2b^2-2a^3b^3+5a^2b^2
=-a^3b^2+7a^2b^2-2a^3b^3

It takes eight hours for a bus and five hours for a car to go from place a to place B. the bus takes more time than the car______ %The speed of a bus is slower than that of a car______ %．

(1) (8-5) △ 5, = 3 △ 5, = 60%; (2) (15 − 18) △ 15, = (840 − 540) × 5, = 38, = 37.5%; so the answer is: 60, 37.5

Simplify the absolute value of m-n. the value of - (n-m) is

Classified discussion
When m > N, the original formula is m-n-n + M = 2m
When m

A train runs 2 / 7 of the whole journey in 4 hours. What's the average part of the whole journey per hour? How many hours can you complete the whole journey according to this calculation

1 / 14
14 hours
Divide 2 out of 7 by 4, which is the fraction of the whole journey in an hour
And then divide it by one, which is the total time

At 1, 2, 3, 4, 5 499500, how many times did the number 2 appear in these numbers
There are more than 57 times in more than 200 pages, guys. 57 times have been scored

First, we calculate the 2:1-100 of the ten places, and there are 10 (2, 12, 22, 32, 42, 52, 62, 72, 82, 92). Note that the 2 of the ten places in 22 is not included for the time being, so a total of 10 * 5 = 50;
If we calculate the 2:1-100 of the ten, there are 10 (20-29), so a total of 10 * 5 = 50;
The last one is 2:200-299, so there are 100;
The final sum: 200