# Affine hull and the subspace

Please clarify a simple doubt that I have. I know that a affine set $X \subseteq \mathbb{R}^n$ contains $0 \in \mathbb{R}^n$ is a subspace in $\mathbb{R}^n$. So

$aff$$\{0,x_1,x_2, ... ,x_n\} = span$$\{x_1,x_2, ... ,x_n \}$ where $aff$$(X)$ i the affine hull of $X$.