Bonjour,
[tex]\overrightarrow{u}=k*\overrightarrow{v}\\\\\left(\begin{array}{c}-9\\ 5\end{array}\right)=k*\left(\begin{array}{c}3\\ t\end{array}\right)\\\\\left\{\begin{array}{ccc}-9&=&k*3\\ 5&=&k*t\end{array}\right.\\\\\\\left\{\begin{array}{ccc}k&=&-3\\t&=&\dfrac{-5}{3}\end{array}\right.\\[/tex]
