Question 421080
{{{3x^7+81x^4}}}=
{{{3x^4(x^3+27)}}}=
{{{3x^4(x^3+3^3)}}}=
{{{3x^4(x+3)(x^2-3x+3^2)}}}=
{{{3x^4(x+3)(x^2-3x+9)}}}