Question

A line with a slope of - 9 passes through the points (1,h) and (2, - 7). What is the value of h?

Answer 1

$\bf \begin{array}{ccccccccc} &&x_1&&y_1&&x_2&&y_2\\ % (a,b) &&(~ 1 &,& h~) % (c,d) &&(~ 2 &,& -7~) \end{array} \\\\\\ % slope = m slope = m\implies \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{-7-h}{2-1}=\stackrel{slope}{-9}\implies \cfrac{-7-h}{1}=-9 \\\\\\ -7-h=-9\implies 2=h$