[tex]\bf \boxed{\stackrel{P}{(-7,16)}\qquad \qquad \stackrel{Q}{(-8,7)}}~\hfill \stackrel{\textit{component form}}{[-8-(-7)~~,~~7-16]} \\\\\\ (-8+7~,~7-16)\implies <\stackrel{a}{-1}~~,~~\stackrel{b}{-9}> \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{magnitude}}{\sqrt{a^2+b^2}}\implies \sqrt{(-1)^2+(-9)^2}\implies \sqrt{82}[/tex]
