Question

Find the equation of the line. the line passes through the points (5, 2) and (- 4, - 4)

Answer 1

to get the equation of any straight line, we simply need two points off of it.

`(\stackrel{x_1}{5}~,~\stackrel{y_1}{2})\qquad (\stackrel{x_2}{-4}~,~\stackrel{y_2}{-4}) ~\hfill~ \stackrel{slope}{m}\implies \cfrac{\stackrel{\textit{\large rise}} {\stackrel{y_2}{-4}-\stackrel{y1}{2}}}{\underset{\textit{\large run}} {\underset{x_2}{-4}-\underset{x_1}{5}}} \implies \cfrac{ -6 }{ -9 } \implies \cfrac{2}{3}`

`\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}{2}=\stackrel{m}{ \cfrac{2}{3}}(x-\stackrel{x_1}{5}) \\\\\\ y-2=\cfrac{2}{3}x-\cfrac{10}{3}\implies y=\cfrac{2}{3}x-\cfrac{10}{3}+2\implies {\Large \begin{array}{llll} y=\cfrac{2}{3}x-\cfrac{4}{3} \end{array}}`