You learned what and can be expanded to, but what about ?
If you use the third algebraic identity, you get
Sometimes you need to rewrite the expression to be able to use the algebraic identities easily. Look at the following example.
You can expand this directly by simply multiplying the parentheses together like you did before. But if you want to be a bit more clever about it, you can rewrite the expression inside the first pair of parentheses slightly:
As , you get