Question

using the slope formula for the points (1,5) and (2,2) what would the denominator be

Answer 1

Let m = slope

m = (2 - 1)/(2 - 5)

You finish.

Answer 2

$\bf (\stackrel{x_1}{1}~,~\stackrel{y_1}{5})\qquad (\stackrel{x_2}{2}~,~\stackrel{y_2}{2}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{2}-\stackrel{y1}{5}}}{\underset{run} {\underset{x_2}{2}-\underset{x_1}{1}}}\implies \cfrac{-3}{1}$