Question

Tarak wants to find the value of a so that the line that passes through (10, a) and (-2, -8) has a slope of value of 1/4.

Explain how Tarak can find the a.​

Answer 1

`(\stackrel{x_1}{10}~,~\stackrel{y_1}{a})\qquad (\stackrel{x_2}{-2}~,~\stackrel{y_2}{8}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{8}-\stackrel{y1}{a}}}{\underset{run} {\underset{x_2}{-2}-\underset{x_1}{10}}} ~~ = ~~\stackrel{\textit{\LARGE m}}{\cfrac{1}{4}} \\\\\\ \cfrac{8-a}{-12}=\cfrac{1}{4}\implies 32-4a=-12\implies 44-4a=0 \\\\\\ 44=4a\implies \cfrac{44}{4}=a\implies \boxed{11=a}`