[ ERoot
    (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ])
    (ENumber "3")
, ESymbol Bin "+"
, ERoot (EIdentifier "x") (ENumber "3")
, ESymbol Bin "+"
, ERoot
    (EFraction NormalFrac (ENumber "3") (ENumber "2"))
    (EFraction
       NormalFrac
       (ERoot (ENumber "3") (EGrouped [ ENumber "3" , EIdentifier "x" ]))
       (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ]))
]