a: A(1;5); B(2;6); C(7;-3)
vecto AB=(1;1)
vecto BC=(5;-9)
vetco AC=(6;-8)
b: \(AB=\sqrt{1^2+1^2}=\sqrt{2}\)
\(AC=\sqrt{5^2+81}=\sqrt{106}\)
\(BC=\sqrt{6^2+8^2}=10\)
d: Tọa độ G là:
\(\left\{{}\begin{matrix}x=\dfrac{1+2+7}{3}=\dfrac{10}{3}\\y=\dfrac{5+6-3}{3}=\dfrac{8}{3}\end{matrix}\right.\)