Expansion of Product of Two Binomials

$(a+b)^{\displaystyle 2} = a^{\displaystyle 2} + b^{\displaystyle 2} + 2ab$

$(a-b)^{\displaystyle 2} = a^{\displaystyle 2} + b^{\displaystyle 2} \,- 2ab$

$(a+b)(a-b) = a^{\displaystyle 2} \,- b^{\displaystyle 2}$