Answer
$-15y^{19/10} -20y^{13/10}$
Work Step by Step
$\begin{array}{ l l }
=-15y\cdot y^{9/10} -20y\cdot y^{3/10} & \begin{array}{l}
\mathrm{Apply\ the\ distributive\ property}\\
a( b+c) =ab+ac
\end{array}\\
& \\
=-15y^{9/10+10/10} -20y^{3/10+10/10} & \begin{array}{l}
\mathrm{Apply\ the\ rule}\\
a^{b} \cdot a^{c} =a^{b+c}
\end{array}\\
& \\
=-15y^{19/10} -20y^{13/10} & \mathrm{Add\ fractions\ to\ simplify}
\end{array}$
