Chapter 5 - Linear Functions - 5-1 Rate of Change and Slope - Practice and Problem-Solving Exercises - Page 296: 19

$m=-1$

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 given coordinates: $m=\frac{3-4}{5-4}$ We simplify above and below the fraction bar with subtraction: $m=\frac{-1}{1}$ We divide the fraction: $m=-1$