Affine space/Basic rules/Exercise

Let ${\displaystyle {}E}$ be an affine space over the ${\displaystyle {}K}$-vector space ${\displaystyle {}V}$. Show the following identities in ${\displaystyle {}V}$.

1. ${\displaystyle {}{\overrightarrow {PP}}=0}$ for ${\displaystyle {}P\in E}$.
2. ${\displaystyle {}{\overrightarrow {PQ}}=-{\overrightarrow {QP}}}$ for ${\displaystyle {}P,Q\in E}$.
3. ${\displaystyle {}{\overrightarrow {PQ}}+{\overrightarrow {QR}}={\overrightarrow {PR}}}$ for ${\displaystyle {}P,Q,R\in E}$.