When Does (A+B)(A-B) = A^2 - B^2?

[charlies1902]

If A and B are n × n matrices, when does
(A + B)(A − B) = A^2 − B^2?

I guess I start out by expanding?

A^2 - BA-B^2+BA=0

Thus AB=BA in order for that to work?

 

[jbunniii]

If A and B are n × n matrices, when does
(A + B)(A − B) = A^2 − B^2?

I guess I start out by expanding?

A^2 - BA-B^2+BA=0

Thus AB=BA in order for that to work?

Correct.