This lecture covers the concept of linear combinations in a vector space of finite dimension, focusing on finding a basis using coordinated applications and matrix form. It explores the pivot method, linear dependence, change of bases, and the dimension of a vector space. The instructor demonstrates how to determine components in a given basis, solve equations, and identify coefficients. Additionally, the lecture discusses the dimensionality of vector spaces, bases characterization, and the properties of canonical bases. Various examples and exercises are provided to illustrate the theoretical concepts.