Question

Find the equation (in terms of x ) of the line through the points ( − 2 , 4 ) and ( 5 , 2 )

Answer 1

$(\stackrel{x_1}{-2}~,~\stackrel{y_1}{4})\qquad (\stackrel{x_2}{5}~,~\stackrel{y_2}{2}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{2}-\stackrel{y1}{4}}}{\underset{run} {\underset{x_2}{5}-\underset{x_1}{(-2)}}} \implies \cfrac{-2}{5 +2} \implies \cfrac{ -2 }{ 7 }$

$\begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{4}=\stackrel{m}{-\cfrac{2}{7}}(x-\stackrel{x_1}{(-2)}) \implies y-4=-\cfrac{2}{7}(x+2) \\\\\\ y-4=-\cfrac{2}{7}x-\cfrac{4}{7}\implies y=-\cfrac{2}{7}x-\cfrac{4}{7}+4\implies y=-\cfrac{2}{7}x+\cfrac{26}{7}$