Question 425652
{{{81a^4-81b^4}}}=
{{{81(a^4-b^4)}}}=
{{{81((a^2)^2-(b^2)^2)}}}=
{{{81(a^2+b^2)(a^2-b^2)}}}=
{{{81(a^2+b^2)(a+b)(a-b)}}}=
{{{3^4(a^2+b^2)(a+b)(a-b)}}}