<<< native
[ EIdentifier "x"
, ESymbol Rel "="
, EFraction
    NormalFrac
    (EGrouped
       [ ESymbol Bin "\8722"
       , EIdentifier "b"
       , ESymbol Bin "\177"
       , ESqrt
           (EGrouped
              [ ESuper (EIdentifier "b") (ENumber "2")
              , ESymbol Bin "\8722"
              , ENumber "4"
              , EIdentifier "a"
              , EIdentifier "c"
              ])
       ])
    (EGrouped [ ENumber "2" , EIdentifier "a" ])
]
>>> eqn
x = {- b +- sqrt {b sup 2 - 4 a c}} over {2 a}