(x+y)/y=3
x+y=3y
x=2y
Объяснение: 1) x/y => 2y/y = 2
2) y/(x+y) => y/(2y+y)= y/3y = 1/3
3) (x-y)/y => (2y-y)/y = y/y = 1
4) y/x => y/2y = 1/2
