Question 204280
Factor completely:
{{{27a^4-125a}}} First factor out an a.
{{{a(27a^3-125)}}} Do you see the difference of cubes in the parentheses?
Do you also recall that:
{{{A^3-B^3 = (A-B)(A^2+AB+B^2)}}}, so we have...
{{{27a^4-125a = highlight(a(3a-5)(9a^2+15a+25))}}}