Question

(2y/y+b+b-y/y)/b2+y2/b+y

Answer 1

(2y/(y+b)+(b-y)/y)/((b²+y²)/(b+y))=((2y²+b²-y²)/(y*(y+b))/((b²+y²)/(b+y)=
=((b²+y²)/(y*(b+y))/((b²+y²)/(b+y))=1/y.