If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: Algebra basics>Unit 5

Lesson 1: Systems of equations intro

# Systems of equations: trolls, tolls (1 of 2)

A troll forces us to use algebra to figure out the make-up of his currency. We end up setting up a system of equations. Created by Sal Khan.

## Want to join the conversation?

• Is it possible to solve this problem using the computer science software on Khan Academy?
• It is possible, although Sal's method is by far the easiest.
• Are there other ways to solves these types of equations?
• And there are other ways too, that look different, and use different specific steps, but are ultimately "equivalent" to the above. Matrix Inversion is one such example. That comes with "Linear Algebra", a more advanced topic. The beauty of using matrices to represent your set of linear equations is how well it lends itself to solutions by machine (as opposed to "by hand").
• sals drawings are really good
• LIKE HOW DID He draw a entire troll
• The troll at the end: Thanks bro I really needed someone to count my loot for me
• Sal is on track to replace both my math and art teacher
• ys fr
• hmm, interesting video.
• fr! How is sal that good at drawing tho
• I went to secondary school in the very late 70s and early 80s. I was pretty good at maths - not the best but OK. I got a good pass in my GCE O level exam - A, if my memory serves me well. But here's the thing - I don't remember doing half of the stuff I've been learning in this Algebra Basics course. We certainly didn't learn about "systems of equations" and I really don't remember doing "X and Y intercepts" and much more besides. 40 years on, things have very much changed.
• Are u like 110 years old or something
• Sal's drawing's are better than Bob Ross lol.
• idk...bob ross has funnier hair