حاصل $\left( {{a}^{۲}}-۴a+۱,a-۳ \right)$ کدام است؟ $\left( a\in \mathbb{Z} \right)$
$\left. \begin{matrix} d|a-3\xrightarrow{\times (a-1)}d|{{a}^{2}}-4a+3 \\ d|{{a}^{2}}-4a+1\to d|{{a}^{2}}-4a+1\,\, \\\end{matrix} \right\}\xrightarrow{-}d|2\Rightarrow d=1\,\,\,ya\,\,\,2$