Respuesta :

[tex]\bf \begin{array}{rllll} \ \textless \ -4&,&2\ \textgreater \ \\ a&&b \end{array}\implies \begin{array}{llll} ||\ \textless \ a,b\ \textgreater \ ||=\sqrt{a^2+b^2}\\\\ ||\ \textless \ -4,2\ \textgreater \ ||=\sqrt{(-4)^2+2^2} \end{array}[/tex]