2 + 3w < -1 < 3w + 5 |subtract 3w from all sides
2 < -1 - 3w < 5 |add 1 to all sides
3 < -3w < 6 |change the signs
-3 > 3w > -6 |divide both sides by 3
-1 > w > -2 → -2 < w < -1 → w ∈ (-2, -1)