This question is question 1 from the 2015 Germany math olympiad contest. I love the fun and creative system of equations! I got the 3b1b plush here: https://store.dftba.com/products/tall-3blue1brown-pi-plushie Subscribe for more math for fun videos 👉 https://www.youtube.com/channel/UC_SvYP0k05UKiJ_2ndB02IA 💪 Support this channel, https://www.patreon.com/blackpenredpen 🛍 Shop math t-shirt & hoodies: null. (10% off with the code "WELCOME10") 🛍 I use these markers: https://amzn.to/3skwj1E