gistfile1.txt

$collection = app(Post::class);
//if tags

$collection = $collection->
 whereHas('tags', function ($query) use ($t) {
            $query->where('tag_id','=', $t);
        });
//if languages
 $collection = $collection->whereHas('languages', function ( $query ) use ( $l ){
            $query->where('language_id', '=',$l);
        });
//if search
 $collection = $collection->where(function ($q) use ($search) {
            $q->where('title', 'LIKE', '%' . $search . '%')
                ->orWhere('explanation','LIKE','%'.$search.'%')
                ->orWhere('usage','LIKE','%'.$search.'%')
                ->orWhere('codeexample','LIKE','%'.$search.'%')
                ->orderBy('id','desc');
});
//get all
 $collection = $collection -> get();