$(n^8)^{\frac{1}{2}}$
$2n^{4}m^{3} \cdot 19n^{2}m^{9}$
$3n^{5}z^{9}(-5n^{3}z^{6})$
$(-3b^{-5}k)(9b^{5}k^{3})$
Write an equivalent expression in simplist form. Assume that variables are not zero.
$(-3k^{5}w^{3})(-13k^{7}w^{9})$