Rearrange (r+s)/8s=(r-s)/8n to make r the subject

Answer 1

multiply both sides by 8sn, the LCD
n(r+s) = s(r-s)
expand
nr + ns = rs - s^2
get all terms containing r to one side
nr - rs = -ns - s^2
take out r as a common factor ...

I will let you finish it