Make r the subject of the relation y = (x-r)/(x+r)

Question

Make r the subject of the relation y =
`(x-r)/(x+r)`

Answer 1

`y=(x-r)/(x+r)\\\\y(x+r)=x-r\\xy+ry=x-r\\ry+r=x-xy\\r(y+1)=x-xy\\r=(x-xy)/(y+1)`