Question 472196
256x4  - 81y4

{{{(16x^2)-(9y^2)^2}}}

{{{(16x^2+9y^2)(16x^2-9y^2)}}}

{{{(16x^2+9y^2)((4x)^2-(3y)^2)}}}

{{{(16x^2+9y^2)((4x+3y)(4x-3y))}}}