Answer
$\color{blue}{-15y^{19/10} - 10y^{13/10}}$
Work Step by Step
RECALL:
(1) $a(b+c) = ab + ac$
(2) $a^m \cdot a^n = a^{m+n}$
Use rule (1) above to obtain:
$=-5y \cdot 3y^{9/10} + (-5y) \cdot 4y^{3/10}
\\=-5y \cdot 3y^{9/10} -5y \cdot 4y^{3/10}
\\=-15y \cdot y^{9/10} - 20y \cdot y^{3/10}$
Use rule (2) above to obtain:
$=-15y^{1+(9/10)} - 20y^{1+(3/10)}
\\=-15y^{10/10+9/10} - 20y^{10/10+3/10}
\\=\color{blue}{-15y^{19/10} - 10y^{13/10}}$
