Question

which of the following best describes the slope of the line below? a. zero b. undefined c. negative d. positive

Explanation:

The line in the graph is a vertical line. The formula for the slope of a line is $m = \frac{y_2 - y_1}{x_2 - x_1}$. For a vertical line, the $x$-coordinates of all points on the line are the same, so $x_2 - x_1 = 0$. Division by zero is undefined, so the slope of a vertical line is undefined.

Answer:

B. Undefined