-3xy根号3y/2x
=-3xy√[3y/(2x)]
=-3xy√[6xy/(2x)²]
=-3xy×√(6xy)×√[1/(2x)²]
=-3xy×√(6xy)×1/(2x)
=-3y√(6xy)/2
m根号2n/m÷n根号2m/n
=m√(2n/m)÷n√(2m/n)
=(m÷n)×√(2n/m÷2m/n)
=(m/n)×√[2n/m× n/(2m) ]
=(m/n)×√(n/m)²
=m/n × n/m
=1