m^2+9n^+6m+6n+10=0
(m+3)^2+(3n+1)^2=0
m+3=0且3n+1=0
所以m=-3,n=-1/3
(m^2-6mn+9n^2)÷(m-3n)-(4m^2-9n^2)÷(2m-3n)
=(m-3n)^2/(m-3n)-(2m-3n)(2m+3n)/(2m-3n)
=m-3n-(2m+3n)
=-m-6n
=3+2=5