Answer
$\color{blue}{-2^{1/2}my^{5/2}}$
Work Step by Step
RECALL:
(1) $a^{m/n}=\sqrt[n]{a^m} = (\sqrt[n]{a})^m$
(2) $(ab)^m=a^mb^m$
(3) $(a^m)^n=a^{mn}$
Use rule (1) above to obtain:
$-m\sqrt{2y^5}=-m(2y^5)^{1/2}$
Use rule (2) above to obtain:
$=-m(2^{1/2})(y^5)^{1/2}$
Use rule (3) above to obtain:
$= -m(2^{1/2})(y^{5(1/2)})
\\=-m(2^{1/2})y^{5/2}
\\=\color{blue}{-2^{1/2}my^{5/2}}$
