Bonjour
Elomanga
[tex]1)\ \overrightarrow{u}=\dfrac{3}{2}\overrightarrow{AB}+\overrightarrow{AC}\\\\\overrightarrow{v}=-2\overrightarrow{AB}+\overrightarrow{AC}\\\\\overrightarrow{w}=0.\overrightarrow{AB}-2\overrightarrow{AC}\\\\\\2)\ \boxed{\overrightarrow{AD}=\dfrac{1}{2}\overrightarrow{AB}+2\overrightarrow{AC}}\\\\\\\boxed{\dfrac{1}{2}\overrightarrow{AD}=\dfrac{1}{4}\overrightarrow{AB}+\overrightarrow{AC}}[/tex]
[tex]2)\ \overrightarrow{u}=\dfrac{3}{2}\overrightarrow{AB}+\overrightarrow{AC}\\\\\overrightarrow{u}=\dfrac{6}{4}\overrightarrow{AB}+\overrightarrow{AC}\\\\\overrightarrow{u}=\dfrac{5}{4}\overrightarrow{AB}+\dfrac{1}{4}\overrightarrow{AB}+\overrightarrow{AC}\\\\\boxed{\overrightarrow{u}=\dfrac{5}{4}\overrightarrow{AB}+\dfrac{1}{2}\overrightarrow{AD}}[/tex]
[tex]\overrightarrow{v}=-2\overrightarrow{AB}+\overrightarrow{AC}\\\\\overrightarrow{v}=-\dfrac{8}{4}\overrightarrow{AB}+\overrightarrow{AC}\\\\\overrightarrow{v}=-\dfrac{9}{4}\overrightarrow{AB}+\dfrac{1}{4}\overrightarrow{AB}+\overrightarrow{AC}\\\\\boxed{\overrightarrow{v}=-\dfrac{9}{4}\overrightarrow{AB}+\dfrac{1}{2}\overrightarrow{AD}}[/tex]
[tex]\overrightarrow{w}=0.\overrightarrow{AB}-2\overrightarrow{AC}\\\\\overrightarrow{w}=\dfrac{1}{2}\overrightarrow{AB}-\dfrac{1}{2}\overrightarrow{AB}-2\overrightarrow{AC}\\\\\overrightarrow{w}=\dfrac{1}{2}\overrightarrow{AB}-(\dfrac{1}{2}\overrightarrow{AB}+2\overrightarrow{AC})\\\\\boxed{\overrightarrow{w}=\dfrac{1}{2}\overrightarrow{AB}-\overrightarrow{AD}}[/tex]