( căn 6 + căn 5)^2 - căn 120

`( \sqrt{6} + \sqrt{5} )^2 - \sqrt{120 }`

`= ( \sqrt{6} )^2 + 2\sqrt{6}. \sqrt{5} + ( \sqrt{5} )^2 - \sqrt{4.30 }`

`= 6 + 2\sqrt{30} + 5 - 2\sqrt{30 }`

`= 6 + 5 + ( 2\sqrt{30} - 2\sqrt{30} )`

`= 11 + 0`

`= 11`