Sharing the Heaviside cover-up method for partial fractions with my son

I got an interesting question on twitter yesterday when I mentioned that my older son was studying partial fractions:

I’d not heard of this method before and though I thought it was interesting I didn’t want to cover it. Changed my mind this morning, though, because I thought it would be fun to show my son that there were interesting ideas that led to non “plug and chug” solutions to partial fraction solutions.

Here’s the introduction:

Here’s my son using the method to solve a problem that we’d worked through yesterday:

Always happy to learn about a new math idea from twitter!