Final answer:
The slope of a line perpendicular to the line (x/4 - y/5 = 1) is -4/1.
Step-by-step explanation:
The equation of the line is given as x/4 - y/5 = 1. To find the slope of this line, we need to rearrange the equation in the form y = mx + b, where m is the slope. Rearranging the equation, we get y = (1/4)x - 1/5.
The slope of the line is the coefficient of x, which is 1/4. The slope of a line perpendicular to this line is the negative reciprocal of the slope.
Therefore, the slope of a line perpendicular to the line with the equation (x/4 - y/5 = 1) is -4/1.