Question

Line N passes through the points (–1, 4) and (–1, –4). Which is true of line N?

Answer 1

$\bf \begin{array}{ccccccccc} &&x_1&&y_1&&x_2&&y_2\\ % (a,b) &&(~{{ -1}} &,&{{4}}~) % (c,d) &&(~{{ -1}} &,&{{ -4}}~) \end{array} \\\\\\ % slope = m slope \implies \cfrac{\stackrel{rise}{{{ y_2}}-{{ y_1}}}}{\stackrel{run}{{{ x_2}}-{{ x_1}}}}\implies \cfrac{-4-4}{-1-(-1)}\implies \cfrac{-4-4}{-1+1}\implies \stackrel{und efined}{\cfrac{-8}{0}}$

check the picture below.