A student adds up rational fractions incorrectly:\frac{a}{b}+\frac{x}{y}=\frac{a+x}{b+y} (\star) Despite that, he sometimes obtains correct results. For a given fraction ba,a,b∈Z,b>0, find all fractions yx,x,y∈Z,y>0 such that the result obtained by (⋆) is correct. number theory proposednumber theory