<<< native
[ ESub (EIdentifier "S") (EText TextNormal "new")
, ESymbol Rel "="
, ESub (EIdentifier "S") (EText TextNormal "old")
, ESymbol Bin "\8722"
, EFraction
    NormalFrac
    (ESuper
       (EDelimited
          "("
          ")"
          [ Right (ENumber "5")
          , Right (ESymbol Bin "\8722")
          , Right (EIdentifier "T")
          ])
       (ENumber "2"))
    (ENumber "2")
]
>>> eqn
S sub {roman "new"} = S sub {roman "old"} - {{left ( 5 - T right )} sup 2} over 2