Answer
$-\frac{1}{3}y^4$
Work Step by Step
Divide the monomials by cancelling out common factors of the numbers and subtracting the exponents of variables.
$\frac{-15y^{13}}{45y^9}=-\frac{15}{45}y^{13-9}=-\frac{1}{3}y^4$
Check the answer.
$45y^9(-\frac{1}{3}y^4)=-\frac{45}{3}y^{9+4}=-15y^{13}$
