Thank you for the opportunity to help you with your question!
Both are important because they help in getting the slope/gradient of the linear graph.With linear inequalities you're basically graphing a line and then
determining whether what's above or below the line will make the
statement true. The line would be the same as if there was an = instead
of > or < so any method you use to graph the line you could also
use to graph the inequality. Then you just have to determine whether
above or below the line makes it true, by using a test point like you
probably always do.
Please let me know if you need any clarification. I'm always happy to answer your questions.