Question

Find the equation that represents the relationship between the variables.

Answer 1

to get the equation of any straight line, we simply need two points off of it, hmmm let's use (0 , 10) and (8 , 30) from the table

$(\stackrel{x_1}{0}~,~\stackrel{y_1}{10})\qquad (\stackrel{x_2}{8}~,~\stackrel{y_2}{30}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{30}-\stackrel{y1}{10}}}{\underset{run} {\underset{x_2}{8}-\underset{x_1}{0}}}\implies \cfrac{20}{8}\implies \cfrac{5}{2}$

$\begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{10}=\stackrel{m}{\cfrac{5}{2}}(x-\stackrel{x_1}{0}) \\\\\\ y-10=\cfrac{5}{2}x\implies y=\cfrac{5}{2}x+10$