#### Answer

$5y(1-xy^3)(1+xy^3)$

#### Work Step by Step

RECALL:
A difference of two squares can be factored using the formula:
$m^2-n^2=(m-n)(m+n)$
Factor out the greatest common factor, $5y$, to obtain:
$=5y(1-x^2y^6)
\\=5y[1^2-(xy^3)^2]$
The binomial is a difference of two squares.
Factor the given difference of two squares using the formula above with $m=1$ and $n=xy^3$ to obtain:
$=5y(1-xy^3)(1+xy^3)$