Question

choose the graph with an undefined slope. a) graph of a positive - sloped line b) graph of a negative - sloped line c) graph of a horizontal line d) graph of a vertical line

Explanation:

Step1: Recall slope formula

The slope formula is $m = \frac{y_2 - y_1}{x_2 - x_1}$. When the denominator $x_2 - x_1=0$, the slope is undefined. This occurs for a vertical line.

Step2: Identify vertical - line graph

Among the given graphs, a vertical line is a graph where all points have the same x - coordinate. Graph d) is a vertical line.

Answer:

d)