Question

Write the point slope form of the equation of the line through the given points: (4,-1) and (-3,1)

Answer 1

`(\stackrel{x_1}{4}~,~\stackrel{y_1}{-1})\qquad (\stackrel{x_2}{-3}~,~\stackrel{y_2}{1}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{1}-\stackrel{y1}{(-1)}}}{\underset{run} {\underset{x_2}{-3}-\underset{x_1}{4}}}\implies \cfrac{1+1}{-7}\implies -\cfrac{2}{7}`

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