## Algebra 1

To find the slope, we use the formula $m=\frac{y_2-y_1}{x_2-x_1}$. We plug in the $x$ and $y$ values from the points shown in the graph: $m=\frac{-1-3}{-1-(-1)}$ We simplify above and below the fraction bar with subtraction: $m=\frac{-4}{0}$ Any time we try to divide by $0$, the answer is undefined. Therefore, we have an undefined slope.