eliminar([], E, []).
eliminar([X|Xs], N, [X|Laux]) :- N =\= X, eliminar(Xs, N, Laux).
eliminar([X|Xs], N, Laux) :- N =:= X, eliminar(Xs, N, Laux).
 
?- eliminar([2,4,6,8,4,5], 4, L), write(L).