[tex]\bf ~~~~~~~~~~~~\textit{distance between 2 points} \\\\ (\stackrel{x_1}{a}~,~\stackrel{y_1}{b})\qquad (\stackrel{x_2}{c}~,~\stackrel{y_2}{d})\qquad \qquad d = \sqrt{\underset{\underset{\textit{horizontal distance}}{\uparrow }}{( x_2- x_1)^2} + ( y_2- y_1)^2} \\\\[-0.35em] ~\dotfill\\\\ \textit{so in short is just }x_2-x_1[/tex]
