Quick links:
How to find inverse functions by operation backtracking
https://www.youtube.com/watch?v=tw6rXG5lPkY
How to do differentiation fast and easy (Part 1)
https://www.youtube.com/watch?v=0cRRr0XYU08
How to do differentiation fast and easy (Part 2)
https://www.youtube.com/watch?v=-xSzUx3w9SA