So the range of b is less than or equal to a.

therefore

m+ 1 & gt； =-2

2m- 1 & lt； =5

Get-3

2. Solution:

A∩B={-3} means that one element in b is -3.

Let's start the discussion.

(1) If a-3=-3, a=0.

Substitute a and b to get:

A={0， 1，-3}，B={-3，- 1， 1}

At this time, A∩B={ 1, -3}

inconformity

(2) If 2a- 1=-3, a=- 1.

Substitute a and b to get

A={ 1，0，-3}，B={-4，-3，2}

A∩B={-3}

To sum up: a=- 1 is what you want.

3. From the meaning of the question, B = {2 2,3} and C = {2 2,4}.

(1) when A∩B=A∪B, A = φ or a = b.

When a = φ, discriminant: a 2-4 (a 2-19) < 0, a 2 > 76/3,

Namely: a < -2√( 19/3) or a & gt2√( 19/3).

When A=B, there are: -a=-5 and a 2- 19 = 6.

Solution: a=5

Based on the above two situations, there are: A

(2) When φ is really contained in A∩B and A ∩ C = φ, A contains element 3, but elements 2 and -4 do not belong to A..

Substituting x=3 into x 2-ax+a 2- 19 = 0, we get: 9-3a+a 2- 19 = 0.

Solution: a=-2 or a=5.

A=-2 generations back, get: x 2+2x- 15 = 0, x = 3 or-5;

If a=5 generations back, we can get: x 2-5x+6 = 0, x = 3 or x=2, give up.

So: a=-2

4. Solution: A∩(CuB)={ 1, 2}

A must have the element 1, 2, while b has no element 1, 2.

Because a ∩ b ≠ φ

1.A={ 1，2，3}，B={3，4，5}

2 A={ 1，2，4}，B={3，4，5}

3 A={ 1，2，5}，B={3，4，5}

4.A={ 1，2，3，4}，B={3，4，5}

5.A={ 1，2，3，5}，B={3，4，5}

6.A={ 1，2，3，4，5}，B={3，4，5}