Question 824625
{{{ 1 - (a +b)^2 }}}
can be rewritten as:
{{{ 1^2 - (a +b)^2 }}}
which is a "difference of squares" -- factors to
{{{ (1 - (a +b))(1 +(a+b)) }}}
{{{ (1-a-b)(1+a+b) }}}