Exclude a category and post_type from wp_query

You can use simply category__not_in parameter to exclude one or several categories from your result.
The sample is like this:

$query = new WP_Query( array( 'category__not_in' => array( 2, 6 ) ) );

To see list of available parameters and complete example, see documentation of WP_Query in developer.wordpress.org

I hope you can use it.