Prove that a topological space is T1 space if and only if every finite subset of X is closed

In this video we continue our course Element of Topology and Functional Analysis Chapter 8 Separation Axioms
In this video you learn about two corollary or Theorem
1- A Space X is T1 if and only if every finite subset of X is closed (Proof)
T1-Space
A space X is T1-Space iff every finite subset of X is closed
Every finite T1-Space is discrete.
Following statements about a topological space X are equivalent.
(a) X is a T1 space;
(b) Each one point subset of X is closed;
(c) Each subset A of X is the Intersection of its open super sets.