Why was the last question that looked at the number in the mirror listed as 10x + Y - 10y-x = 63?

Why was the last question that looked at the number in the mirror listed as 10x + Y - 10y-x = 63?

In the hypothesis, X and y are all numbers (that is, X and y are any number from 1 to 9)
For example, 23 = 2 * 10 + 3, 45 = 4 * 10 + 5 (that is, ten digits plus one digit)
So xy = x * 10 + y and its opposite number is YX = y * 10 + X
The difference between them is 63, so XY - YX = 10x + Y - (10Y + x) = 63
After simplification, X - y = 7, (x is 7 larger than y), so x can only be 8 and 9, and y can only be 1 and 2
The two digits they make up are 81 and 92, and the opposite numbers are 18 and 29
So the two numbers are 81, 18 and 92, 29

5x-6=2/9x+1

(5-2/9)x = 7
43/9x = 7
x = 63/43

On line solution of 5x + 9x-120 = 0
As above

Using formula method
x1=[-9-√(9^2+4×5×120)]/(2×5)=(-9-√2481)/10
x2=[-9+√(9^2+4×5×120)]/(2×5)=(-9+√2481)/10

The solution of equation 2 / 3 [2 (x-1 / 3)] = 5x is?

2/3×[2(x-1/3)]=5x
If you multiply three on both sides, you'll get three
2×[2(x-1/3)]=15x
4（x-1/3）=15X
4X-4/3=15X
-11X=4/3
X=4/3÷（－11）
X＝－4/33

9x-3 in 16 = 5x in 4

9x-3 in 16 = 5x in 4
Multiply both sides by 16
9x-3=4*5x
9x-3=20x
11x=-3
x=-3/11
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9x-20 + 16 = 5x steps and tests to solve the equation

9x-20+16=5x
9x-4=5x
9x-5x=4
4x=4
x=1
Inspection:
Take x = 1 to the left
9x1-20 + 16 = 5 = right
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4X + 8 = 5x + 28x + 16 = 10x-202 + 9x-6 = 8
=8x

4x+8=5x+2
5x-4x=8-2
x=6
8x + 16 = 10x-20
10x-8x=16+20
2x=36
x=18
One = 2x + 6
9x-8x=6-2
x=4

9x-0.8x80% = 5x, solve the equation

9x-0.64=5x
4x=0.64
x=0.16

How to solve the problem that the square of x minus 2x plus 2A minus a is less than or equal to 0

x²-2x+2a-a²≤0
That is, (x-a) [x - (2-A)] ≤ 0
① When a = 2-A, i.e. a = 1
The solution of the inequality is x = 1
② When a > 2-A, i.e. a > 1
The solution of the inequality is 2-a