Question 764025
There is a common rule for examples like that.


{{{(a+b)(a-b)}}}
{{{(a+b)a-(a+b)b}}}
{{{a^2+ab-(ab+b^2)}}}
{{{a^2+ab-ab-b^2}}}
{{{a^2-b^2}}}


In short, this is the rule:  {{{highlight((a+b)(a-b)=a^2-b^2)}}}