Work Step by Step
RECALL: A vertical line has an undefined slope and has an equation of the form $x=h$ where $h$ the x-coordinate of all the points on the line. The line has an undefined slope therefore the line must be vertical. The vertical line passes through the point $(-1, 4)$. The x-coordinate of the point $(-1, 4)$ is $-1$. Thus, the equation of the line is $x=-1$.