<<< native
[ EFraction
    NormalFrac
    (ERoot
       (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ])
       (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ]))
    (ERoot
       (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ])
       (EGrouped [ ENumber "3" , EIdentifier "x" ]))
, ERoot (EIdentifier "x") (ENumber "3")
]
>>> tex
\frac{\sqrt[{x - 3}]{x - 3}}{\sqrt[{x - 3}]{3x}}\sqrt[x]{3}