Find the slope of a line parallel to the line whose equation is \( 10 x+12 y=-120 \). Fully simplify your answer.

To find the slope of a parallel line, we first need to determine the slope of the given line from its equation \( 10x + 12y = -120 \). We can rewrite this equation in slope-intercept form (y = mx + b) by isolating y: 1. Subtract \( 10x \) from both sides: \( 12y = -10x - 120 \) 2. Divide all terms by 12: \( y = -\frac{10}{12}x - 10 \) 3. Simplifying \(-\frac{10}{12}\) gives \(-\frac{5}{6}\). The slope (m) of the line is \(-\frac{5}{6}\). Since parallel lines have the same slope, the slope of a line parallel to this one is also \(-\frac{5}{6}\). Thus, the fully simplified answer is \[ \boxed{-\frac{5}{6}}. \]