3x-5y=0
3x=5y
x/y=5/3
(x-2y)/(x+3y)
=(x/y-2y/y)/(x/y+3y/y)
=(x/y-2)/(x/y+3)
=(5/3-2)/(5/3+3)
=(-1/3)/(14/3)
=-1/3*3/14
=-1/14