5 The variables \(x\) and \(y\) are related by the differential equation
$$x ^ { 3 } \frac { \mathrm {~d} y } { \mathrm {~d} x } = x y + x + 1 .$$
- Use the substitution \(y = u - \frac { 1 } { x }\), where \(u\) is a function of \(x\), to show that the differential equation may be written as
$$x ^ { 2 } \frac { \mathrm {~d} u } { \mathrm {~d} x } = u .$$
- Hence find the general solution of the differential equation (A), giving your answer in the form \(y = \mathrm { f } ( x )\).