This lecture discusses the transformation of a general explicit scalar ODE of order n into an equivalent system of n 1st order ODEs. The process involves defining a vector-valued function and casting the scalar ODE into a vectorial form. The lecture also covers the conditions for the existence and uniqueness of solutions to the system of ODEs, emphasizing the relationship between solutions to the scalar ODE and the system of first-order ODEs. Practical examples and applications are provided to illustrate the concepts discussed.