Question 45609
{{{3p^4  + 16p^3  + 21p^2}}}
{{{p^2(3p^2  + 16p  + 21)}}}
{{{p^2(3p^2  + 7p + 9p + 21)}}}
{{{p^2((3p^2  + 7p) + (9p + 21))}}}
{{{p^2(p(3p  + 7) + 3(3p + 7))}}}
{{{p(p)(p + 3)(3p + 7)}}}
{{{p(p + 3)(3p^2 + 7p)}}}
length = {{{3p^2 + 7p}}}