Because of ax? The solution set of +bx+ 1 > 0 is {x |- 1
So {a
-b/a=- 1 + 1/3 =-2/3
1/a = - 1/3
The solution is {a=-3.
b= 2
So ab=-6
The first is a<, a; , one
2.
Solution: y= 1-6x-x? =-(x? +6x- 1)=-[(x+3)? - 10]= 10-(x+3)? ,
Because (x+3)? ≥0,
So 10-(x+3)? ≤ 10,M = { y | y≤ 10 };
Similarly, y=5+2x-x? =6-(x- 1)?
Because (x+ 1)? ≥0,
So 6-(x+ 1)? ≤ 10,M = { y | y≤6 };
To sum up, we can see that n is indeed included in m.
3.
That is to say, 3x+ 1 = x 2-x+a+ 1, x 2-4x+a = 0 has a solution, that is, 4 2-4a > = 0a ≤ 4. Since A is a positive integer, A takes the value of 1, 2,3,4.
Description: A∩B≠ empty set means that A and B have the same elements.
4.
Let f(x)=kx? +( 1-k? )x-kδ=( 1-k? )? +4k? =( 1+k? )? >0
1. If k=0, it is not valid.
2. If k < 0, the parabola opens downward, it can be found that only F (-2) > 0 and F (2) > 0 are needed to satisfy the problem conditions.
Solution: k does not exist.
3. If k > 0, the opening is upward and the symmetry axis has three positions:
① On the left side of -2 ② On the right side of 2 ③ Between -2 and 2.
Combined with δ > 0, it can be seen that none of the three cases can be established. Symmetry axis x=(k? -1)/2k. Therefore: ① x=(k? - 1)/2k 0。
②x=(k? -1)/2k > 2 and f (2) > 0. The solution is -2+√ 5 < k < 2.
To sum up, we can get: -2+√ 5 < k < 2.