Find the equation of the line passing through (0, -1) and parallel to the y- axis.

The equation of a line can be represented in the form y = mx + b, where m is the slope of the line and b is the y-intercept (the point where the line intersects the y-axis). Since the line is parallel to the y-axis, its slope is undefined (division by zero is not defined). Therefore, the equation of the line cannot be represented in the form y = mx + b. However, we know that the line passes through the point (0, -1). This means that the x-coordinate of every point on the line is 0 (since the line is parallel to the y-axis and does not move horizontally). Therefore, the equation of the line is x = 0. This equation means that every point on the line has an x-coordinate of 0, which is the y-axis. So, the line is simply the y-axis itself. Thus, the answer is x = 0.