已知4x=9y求(1)x+y/y (2)y-x/2x
问题描述：
已知4x=9y求(1)x+y/y (2)y-x/2x
有关比例的
答
4x=9y
x=9/4*y
(1)(x+y)/y
=[(9/4)y+y]/y
=(9/4+1)y/y
=9/4+1
=13/4
(2)(y-x)/2x
=[y-(9/4)y]/[2*(9/4)y]
=(1-9/4)y/(2*9/4)y
=(9/5)/(9/2)
=2/5