What is the difference of two squares?

• A “Difference Of Two Squares” is any expression in the form p²?– q²

Why is it so important?

• It comes up a lot – recognising it can save a lot of time

How does it factorise?

• p²?– q²?can always be factorised in the same way:p²?– q²?= (p + q)(p – q)

  (Try multiplying it out to see why…)