Question 114366
{{{a^2(b-c)-16b^2(b-c)}}}


First step is to factor out the (b-c),
{{{(a^2-16b^2)(b-c)}}}


Now recognize that {{{a^2-16b^2}}} is the difference of two squares that factors as {{{(a-4b)(a+4b)}}}.


So the complete factorization is:  {{{(a-4b)(a+4b)(b-c)}}}.