Ответ:

(√22 - √33) / √6 = (√(2*11) - √(3*11)) / √6 = (√11 * (√2 - √3)) / √6 ≈ (3.317 * (1.414 - 1.732)) / 2.449 ≈ (3.317 * -0.318) / 2.449 ≈ -1.055 / 2.449 ≈ -0.43