To calculate the slope of the line based on the two points \((-4,5)\) and \( (8,-1) \), we use the formula for the slope \( m \):
\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Here, let's assign:
- \( (x_1, y_1) = (-4, 5) \)
- \( (x_2, y_2) = (8, -1) \)
Now, substitute the values into the formula:
\[ m = \frac{-1 - 5}{8 - (-4)} \]
Calculating the differences in the numerator and the denominator:
\[ m = \frac{-6}{8 + 4} = \frac{-6}{12} \]
Now simplify the fraction:
\[ m = \frac{-1}{2} \]
Therefore, the slope of the line is
\(\boxed{-\frac{1}{2}}\).