3√(11+6√2 )-√(19-6√2)

= 3√(11) + 3√(6√2) - √(19) + √(6√2)
= 3√11 + 6√2 - √19 + √6√2

Therefore, 3√(11+6√2 )-√(19-6√2) simplifies to 3√11 + 6√2 - √19 + √6√2.