NetBusters has a $30 sign-up fee plus $1.25 per video BlockFlix has a $10 sign-up fee plus $2.25 per video

Question

How do I set up a function rule equation

I assume that you want to find out how many videos you have to buy before they become equal. Consider this:

There is a $20 difference in sign-up fees and a dollar difference per video. Let X = number of videos ordered.

(30-10) - (2.25-1.25X) = 0

I hope this helps. If not, repost your question in more detail. Thanks for asking.