Réponse :
Bonjour,
Explications étape par étape :
[tex]M=mil[AB]\Longleftrightarrow\ \overrightarrow{AB}=2*\overrightarrow{AM}\\\\\left(\begin{array}{c}x-1\\ y-5\end{array}\right)=2*\left(\begin{array}{c}-3-1\\ -2-1\end{array}\right)\\\\\\\left(\begin{array}{c}x-1\\ y-5\end{array}\right)=\left(\begin{array}{c}-8\\ -14\end{array}\right)\\\\\\\left(\begin{array}{c}x\\ y\end{array}\right)=\left(\begin{array}{c}-8+1\\ -14+5\end{array}\right)\\\\\\\left(\begin{array}{c}x\\ y\end{array}\right)=\left(\begin{array}{c}-7\\ -9\end{array}\right)\\\\\\x=-7[/tex]
