Question

Two points determine a line. Find an equation of the line passing through the points.

​(2​,−7​) and ​(5​,−19​)

An equation of the line is y=

Answer 1

`(\stackrel{x_1}{2}~,~\stackrel{y_1}{-7})\qquad (\stackrel{x_2}{5}~,~\stackrel{y_2}{-19}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{-19}-\stackrel{y1}{(-7)}}}{\underset{run} {\underset{x_2}{5}-\underset{x_1}{2}}} \implies \cfrac{-19 +7}{3} \implies \cfrac{ -12 }{ 3 } \implies - 4`

`\begin{array} \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}{(-7)}=\stackrel{m}{- 4}(x-\stackrel{x_1}{2}) \implies y +7 = - 4 ( x -2) \\\\\\ y+7=-4x+8\implies {\Large \begin{array}{llll} y=-4x+1 \end{array}}`