<em>If the line is a vertical line on a graph, then this means that the </em><em>x coordinate is 0</em><em> while the </em><em>y-intercept is un-identified.</em><em> Looking at the options and the formula, </em><em>x = 0 </em><em>is the most reasonable option because a </em><em>vertical line on a coordinate plane basically defines that the x coordinate is 0.</em>