If 2x-5x + (8 / 2x-5x + 1) - 5 = 0, then the value of 2x-5x-1 is

If 2x-5x + (8 / 2x-5x + 1) - 5 = 0, then the value of 2x-5x-1 is

Well, I suggest you review the third grade textbook

The square of 2x-5x-6 = 0

2x^2 -5x =6
=>x^2 - (5/2)x=3
=>x^2 - 2x*(5/4) +(5/4)^2 =3 +(25/16)
=>(x- 5/4 )^2 =73/16
=>x - 5/4 = ±√(73/16)
=> x=5/4 ±(√73 )/4 = (5±√73)/4

If the square of 2x minus 5x + 5 = 0
Find the value of (15x's Square - 18x + 9) - (- 3x + 19x + 31) - 8x

The square of 2x - 5x + 5 = 0
2x^2-5x=-5
(15x squared - 18x + 9) - (- 3x ^ 2 + 19x + 31) - 8x
=18x^2-45x-22
=9(2x^2-5x)-22
=9*(-5)-22
=-45-22
=-67

Calculate log2 (1 + 2 + 3) + log2 (1 + 2 + 3)

Log2 (1 + radical 2 + radical 3) + log2 (1 + radical 2 - radical 3)
=log2[(1+√2+√3)(1+√2-√3)]
=log2[(1+√2)²-(√3)²]
=log2[2√2]
=log2[2^(3/2)]
=3/2
Have a good time!

The sum of 36% and 9% of a number is 315

Solution 1
315÷（36%+9%）
=315÷45%
=700
Solution 2
Let this number be X
36%X+9%X=315
45%X=315
X=315*100/45
X=700
A: the number is 700
I hope my answer will help you

There is an integer n, can you judge whether n + N and N + N + 1 are odd or even? Try to verify your conclusion with an example
Come on, I only need the first three respondents to get a reward!

N + n = 2n, even number
N + N + 1 = 2n + 1, odd
For example: n = 3
N + n = 6, even number
N + N + 1 = 7, odd

Simplify the square of a minus 2A plus the square of a minus 1 divided by a cubic minus a quadratic a plus 1

[(a^2 -1)/(a^2-2a+1)]/[(a+1)/(a^3 -a^2)] =[(a+1)(a-1)/(a-1)^2]x[a^2(a-1)/(a+1)] =a^2/(a-1)^2 =[a/(a-1)]^2

5: 5 / 12 reduction ratio

The division sign
5: 5 / 12 = 5 divided by 5 / 12 = 5 multiplied by 12 / 5 = 12

What's the superposition method? Superposition, multiplication, dislocation, subtraction, reverse order, addition, split term, cancellation? I'm totally confused. Someone can help me summarize

Accumulation: the difference between the latter and the former forms an arithmetic sequence
Cumulative multiplication: the difference between the latter and the former is a series of numbers
Dislocation addition: dislocation subtraction
It is mainly used in the case that the equal ratio sequence and the equal difference sequence want to multiply. The method is to multiply the common ratio and then dislocation
Let's take an example
For example, an = 1 / 2 ^ n
Let s = 1 / 2 + 1 / 4 + 1 / 8 +. + 1 / 2 ^ n
2S=1+1/2 + 1/4 +1/8 + .+1/2^（n-1）
S = 1-1 / 2 ^ n
An=n/2^n
Let s = 1 / 2 + 2 / 4 + 3 / 8 +. N / 2 ^ n
2S= 1 + 2/2 + 3/4+.n/2^(n-1)
After dislocation cancellation
S=（1+1/2+1/4.+1/2^(n-1) )-n/2^n
=2- 1/2^(n-1)-n/2^n
Addition in reverse order: generally used for summation of arithmetic sequence
For example, 1 + 2 + 3 + 4 +. + 99 + 100 is written as 100 + 99 + 98 + 97 +... + 2 + 1
It's 100 101's, and then it's divided by two
This method is used in a narrow range, unless there is a special sequence
For example, an + A1 = constant
Split term cancellation: typically used for an arithmetic sequence * an arithmetic sequence
In this case, summation must be a split term

When x = - 1, y =? X = - 2, y =? X = 1, y =? X = 2, y =? X = 2?

X=-1,Y=-3/2X=-2,Y=-2,X=1,Y=5/2X=2,Y=6.