If set a = {x | X-1 ≤ 2} set B = {x | x ＞ a}, and a ∩ B = empty set, find the value range of real number a

If set a = {x | X-1 ≤ 2} set B = {x | x ＞ a}, and a ∩ B = empty set, find the value range of real number a

Because a = {x | x ≤ 3} and B = {x | x ＞ a}
If a ∩ B = an empty set, then the intersection of a and B is empty, so a > 3

If the solution set of (M + 1) x ＜ m + 1 is x ＞ 1, find the value range of M

lt;0 ,∴（x2-8x+20)>0 .
The original inequality is: MX2 + 2 (M + 1) x + 9m + 4 & lt; 0, if M = 0, then the solution set is r
If the solution set is r, then only △ & lt; 0 is needed
∴4(m+1)^2 < 4m(9m+4) ,∴m^2 + 2m + 1 < 9m^2 + 4m
‖ 8m ^ 2 + 2m - 1 & gt; 0, ‖ (2m + 1) (4m-1) & gt; 0, ‖ M & lt; - 1 / 2, or M & gt; 1 / 4

If (m-1) x > 1-m, the solution set is X

In fact, the discussion is divided into situations, and then skilled point can directly get the results!
(1) When M-1 > 0, i.e. m > 1
x>(1-m)/(m-1)=-1
It is contrary to the condition, so the hypothesis is not tenable
（2）m-1

Given the set a = {X / X1} set B - {X / 2m ≤ x ≤ m + 3} if B ∈ a, the value range of M is obtained
Maybe it's hard? Where are you

B is a subset of a, so 2mm + 3,
The solution is m3

Let m = {X / - 1 ≤ X

x-k

Given the set M = {K | K + 1 ≤ x ≤ 2K}, n = {x | 1 ≤ x ≤ 3}, and M is a subset of N, find the value range of K

k+1>2x
x

Let m = {X / - 2 less than or equal to x less than or equal to 5} and N = {X / A + 1 less than or equal to x less than or equal to 2a-1}. If n is a subset of M, the value range of a is obtained

(1) When set n is not an empty set
2a—1≥a+1
a≥2
And M = {x | - 2 ≤ x ≤ 5},
n={X|a+1≤x≤2a—1}
If n is a subset of M
Then - 2 ≤ a + 1 and 2a-1 ≤ 5
To sum up, the solution is: 2 ≤ a ≤ 3
(2) When set n is an empty set
2a—1

Set M = x (x-1 less than or equal to x less than 2) n = x (x-k less than or equal to 0) if M ∩ n = m, then the value range of K is greater than or equal to 2
?

In set M is X-1

Set M = {X / - 1 ＂ x ＂ 2}, n {absolute value x is greater than or equal to a}, m intersection n = empty set, the value range of a

a>2

Let m = {x | - 1 ≤ X

N={X|X-K≥0},
N={X|X≥k},
Mark on the number axis
Set M = {x | - 1 ≤ x