Risolto!
codice:
$(".open").live('click', function(){    
    var slide = "#d"+this.id.replace('a','');
    $(slide).animate({"height": "show"}, { duration: 500 });
    });
$(".close").live('click', function(){
    var slide = "#d"+this.id.replace('c','');
    $(slide).animate({"height": "hide"}, { duration: 500 });
    });