Solve -3 less than / equal to n + 6 less than / equal to 7

If I understand what you are trying to ask, and your solving for n
It would be -9==< : means less than or equal to

I think it could be -2, -1, and 1

Any other positive number greater than 1 makes it false.

-2 + 6 = 4
-1 + 6 = 5
1 + 6 = 7

All of these make the statement true because 4, 5, and 7 are all greater than -3 and less than 7, and 7 is equal to 7.