Bài ` 1 : `

Đặt ` A ` cho biểu thức trên ta có ` : `

` A = (sqrt{6} - sqrt{3})/(sqrt{2}-1) - sqrt{27} + 6/(sqrt{3}) `

` A = ( sqrt{6} - sqrt{3} ) . ( sqrt{2} + 1 ) - sqrt{27} + 6/(sqrt{3}) `

` A = ( sqrt{6} - sqrt{3} ) . ( sqrt{2} + 1) - 3sqrt{3} + 6/(sqrt{3}) `

` A = ( sqrt{6} - sqrt{3} ) . ( sqrt{2} + 1 ) - 3sqrt{3} + 2sqrt{3} `

` A = sqrt{12} + sqrt{6} - sqrt{6} - sqrt{3} - 3sqrt{3} + 2sqrt{3} `

` A = sqrt{12} - sqrt{3} - 3sqrt{3} + 2sqrt{3} `

` A = 2sqrt{3} - sqrt{3} - 3sqrt{3} + 2sqrt{3} `

` A = 0 `

Vậy ` A = 0 `

` text{#Antanezha} `