(-2)^3)/(-2+1/3)=-8/(-5/3)=24/5=4,8
2) =b^2/(5a)
3) =((m-n)(m+n)-k(m-n))/((k-n)(k+n)-(k+n)m)=((m-n)(m+n-k))/((k+n)(k-n-m))=-(m-n)/(k+n)
.........................................................................
