Question 951347

{{{4a^3 -20a^3 -8a}}}....add terms with same exponent first

{{{ -16a^3 -8a}}}....if both terms negative, we can factor out {{{-1}}}

{{{ -1(16a^3 +8a)}}}.....as you can see, both terms are divisible by {{{8a}}}, so factor it out

{{{ -8a(2a^2 +1)}}}...your answer