Question

What is the value of y for the line that had a slope of -3/2 and passes through the points (3,5) and (7,y)?

Answer 1

$\bf (\stackrel{x_1}{3}~,~\stackrel{y_1}{5})\qquad (\stackrel{x_2}{7}~,~\stackrel{y_2}{y}) \\\\\\ slope = m\implies \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{y-5}{7-3}=\stackrel{\stackrel{slope}{\downarrow }}{-\cfrac{3}{2}}\implies \cfrac{y-5}{4}=-\cfrac{3}{2} \\\\\\ 2y-10=-3y\implies 5y-10=0\implies 5y=10\implies y=\cfrac{10}{5}\implies y=2$