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