গুণিতক

${\displaystyle (x+y)(x-y)=x^{2}-y^{2}}$
${\displaystyle (x+y)(x^{2}-xy+y^{2})=x^{3}+y^{3}}$
${\displaystyle (x+y)(x+y)=x^{2}+2xy+y^{2}}$
${\displaystyle (x-y)(x-y)=x^{2}-2xy+y^{2}}$