Question

How do you multiply binomials `(a+b)(a-b)`?

Answer 1

This is a special pattern called the difference of squares.

If we FOILed this out:
`(a+b)(a-b)`
`(a^2-ab+ab-b^2)`

Notice how the two middle terms cancel. You now have the important pattern:
`(a+b)(a-b) = (a^2-b^2)`