Resposta :
[tex]\Large\displaystyle\text{$\begin{gathered}\tt d_{AB}=\sqrt{(x_{B} -x_{A})^{2}+(y_{B} -y_{A})^{2}}\end{gathered}$}[/tex]
[tex]\Large\displaystyle\text{$\begin{gathered}\tt d_{AB}=\sqrt{(7-3)^2+(9-6)^2} \end{gathered}$}[/tex]
[tex]\Large\displaystyle\text{$\begin{gathered}\tt d_{AB}= \sqrt{(4)^2+(3)^2}\end{gathered}$}[/tex]
[tex]\Large\displaystyle\text{$\begin{gathered}\tt d_{AB}= \sqrt{16+9}\end{gathered}$}[/tex]
[tex]\Large\displaystyle\text{$\begin{gathered}\tt d_{AB}=\sqrt{25} \end{gathered}$}[/tex]
[tex]\Large\displaystyle\text{$\begin{gathered}\boxed{\tt d_{AB}=5} \end{gathered}$}[/tex]