Question

The points (6,9) and (8,j) fall on a line with a slope of – 7. What is the value of j?

Answer 1

`(\stackrel{x_1}{6}~,~\stackrel{y_1}{9})\qquad (\stackrel{x_2}{8}~,~\stackrel{y_2}{j}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{j}-\stackrel{y1}{9}}}{\underset{run} {\underset{x_2}{8}-\underset{x_1}{6}}} \implies \cfrac{j -9}{2}~~ = ~~\stackrel{\stackrel{m}{\downarrow }}{-7}\implies j-9=-14\implies j=-5`