How do I show entries that do not have a certain category? I’m aware of the relatedTo() parameter for entries that belong to a category but how can I show entries that are NOT relatedTo() a certain category?
I found this to work, although maybe there’s a better method.

{% set excludedCategory = craft.categories.id('100') %}
{% set excludedEntries = craft.entries.section('blog').status('live').relatedTo(excludedCategory).ids() %}

{% set entryIds = craft.entries.section('blog').status('live').ids() | without(excludedEntries) %}
{% set entries = craft.entries.section('blog').status('live').id(entryIds) %}