Special Linear Group is not Abelian

Theorem
Let $K$ be a field whose zero is $0_K$ and unity is $1_K$.

Let $\SL {n, K}$ be the special linear group of order $n$ over $K$.

Then $\SL {n, K}$ is not an abelian group.

Proof
From Special Linear Group is Subgroup of General Linear Group we have that $\SL {n, K}$ is a group.

From Matrix Multiplication on Square Matrices over Ring with Unity is not Commutative‎ it follows that $\SL {n, K}$ is not abelian.