int(((x^5+x^4-8 ) /(x^3+4x))dx)=
=int((x^2+x-4+((-4x^2+16x-8 ) /(x^3+4x))dx)=
=x^3/3+x^2/2+int(((-4x^2+16x-8 ) /(x^3+4x))dx)