carbon subtract days from code example

Example 1: carbon subdays

$users = Users::where('status_id', 'active')
           ->where( 'created_at', '>', Carbon::now()->subDays(30))
           ->get();

Example 2: carbon subtract two dates

$date = Carbon::parse('2016-09-17 11:00:00');
$now = Carbon::now();

$diff = $date->diffInDays($now);