My book is a little more interesting than hers

My book is a little more interesting than hers

My book is a little more interesting than hers!

When a () is a true fraction, there are () true fractions, when a () is a false fraction, there are () false fractions
When a () is true fraction, there are () true fractions, when a () is false fraction, there are () false fractions

When a > 9, it is a true fraction=

All natural numbers are integers, and all integers are natural numbers______ (judge right or wrong)

From the analysis, we can see that natural numbers are integers and integers are natural numbers

1.5.11.10.21.15.31
1.5.11.10.21.15.31. ()

20.41

For any natural number n, can the algebraic formula (n + 11) ^ 2 - (N-9) ^ 2 be divisible by 4, why?

Square difference formula:
(n+11)^2-(n-9)^2
=(2n+2)*20=4*10*(n+1)
It's divisible by four

There's another question, oh, 1 / 2 of a times 1 / 4 of a times 3 / 8 of a (a > 0). This is an exponential function

I answered just now
a^(1/2) * a^(1/4) * a^(-3/8)
= a^(1/2 + 1/4 - 3/8)
= a^(3/8)

i don not know what i should do next

I do not know what to do next

Given that the solution of the equation 4x + 5K = 3 about X is x = 2, find the solution of the equation 2 + K (2y-1) = - KY about y

x=2
Substitution equation
8-5k=3
5k=5
k=1
So the following is 2 + (2y-1) = - Y
2y+1=-y
2y+y=-1
3y=-1
y=-1/3

Basic knowledge points of linear inequalities with one variable
The solution set of the inequality system can be expressed on the number axis. When using the number axis to represent the solution set of the inequality system, we should pay attention to two determinations. One is to determine the boundary point (what is the boundary point). If the boundary point is the solution of the inequality system, it should be represented by a solid circle or a hollow far point; if the boundary point is not the solution of the inequality system, it should be represented by a solid circle or a hollow far point, And why

Each inequality is drawn on the number axis, and then according to their intersection to determine the solution set, that is, the answer

The average of five numbers is 60. If one of them is changed to 80, the average will be 70. What is the original number?

70 × 5-60 × 5 = 350-300 = 5080-50 = 30