` Bài    2`

`a)sqrt45:sqrt80`

`=sqrt{45/80}`

`=sqrt{9/16}`

`=3/4`0

`b)sqrt{(2*3)^5}:sqrt{(2^3*3^5}`

`=sqrt{(2*3)^5:(2^3*3^5)}`

`=sqrt{2^5*3^5:2^3*3^5}`

`=sqrt2^2`

`=2`

`c)sqrt54:sqrt2:sqrt3`

`=sqrt{54:2:3}`

`=sqrt{54:6}`

`=sqrt9`

`=sqrt3^2`

`=3`

`d)sqrt3/sqrt75:sqrt52/sqrt117`

`=sqrt(3/75):sqrt(52/117)`

`=sqrt1/25:sqrt(4/9)`

`=1/5:2/3`

`=1/5*3/2`

`=3/10`