For those that need a concise refresher on - or introduction to - linear equations there's an (as usual) excellent series of 15 short videos from 3blue1brown:

For those that need a concise refresher on - or introduction to - linear equations there's an (as usual) excellent series of 15 short videos from 3blue1brown: https://youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab https://youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFit...