Use eight beads to dial out four digits on the counter. What is the maximum number and what is the minimum number?

Max 8000 min 1007

Are these two quadratic radicals of the same kind?
Why √ this is the root sign

No
√A*√AB =A√B
√B*√AB =B√A

The method to determine the value range of the independent variable: 1. When the independent variable appears in the form of integral, its value range is_ When the independent variable appears in fractional form
Then the value range is the denominator When the independent variable appears in the form of even root, its value range is to make the number to be square_ When the root of odd power appears, its value range is____ ；
This is a very urgent problem. Although it is very simple, I have long forgotten it. I hope you can help me with the ending

The methods to determine the value range of the independent variable are as follows: 1. When the independent variable appears in the form of integral, its value range is (all real numbers); 2. When the independent variable appears in the form of fraction, its value range is the real number that makes the denominator (not equal to 0); when the independent variable appears in the form of even root, its value range is to make the square number to be (non negative); when the independent variable appears in the form of odd root, its value range is to make the square number to be (non negative), Its value range is (all real numbers)

When the function relation is fractional, what is the value range of the independent variable?

The set of independent variables whose denominator is not zero

Fraction X-1 / X-7, the value range of independent variable x

The denominator cannot be 0, so X-7 ≠ 0, X ≠ 7

When the function relation is fractional, the value range of the independent variable is

Let the fraction be equal to zero, then the answer is assumed to be a, and the final answer is independent variable, not equal to a

2. In the function y = √ X-1, the value range of the independent variable is? If the value of fraction X-2 / X-1 is zero, then x =?

In the function y = √ X-1, the value range of the independent variable is x ≥ 1 (because X-1 ≥ 0 can deduce ≥ 1)
If the value of fraction X-2 / X-1 is zero, then x = 2 (X-2 / X-1 = 0, x = 2 can be deduced if X-2 = 0 and X-1 ≠ 0)

What are the independent variables and function expressions of a function?

The expression of a function is y = KX + B, where x is the independent variable and Y is the dependent variable
In practice, the relationship between independent variables and dependent variables is the function expression, and the above y = KX + B is the general expression of a function

Define the operation : X y = x (1-y) on R if the inequality (x-a) * (x + a)

（x-a)*(x+a)=(x-a)(1-x-a)=-x^2+x+a^2-a

Use eight beads to dial out four digits on the counter. What is the maximum number and what is the minimum number?