x & lt2 1
Solving inequality 2
x & gt2-3a
Combine the two solutions.
2-3a & lt; x & lt2 1
X has four integer solutions, which are 20, 19, 18 and 17.
So 16
-5 & lt; a & lt=- 14/3
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Solved already
2-3a & lt; x & lt2 1
This inequality has only four integer solutions,
So these four solutions can only be 20, 19, 18, 17.
If 2-3a= 17,
Then 17
Therefore, 2-3a
If 2-3a= 16,
So 16
X can get the integer solution of 17.
In this way, we can get four integer solutions of 20, 19, 18 and 17, which meet the conditions.
So it is 16 ≤ 2-3a < 17,
Solve -5 in this way