Question 199103
Find an equation of a line perpendicular to 2x-5y=20?
The slope of 2x-5y=20 is +2/5.  Lines perpendicular to it will have a slope, m, that's the negative inverse, = -5/2
Those lines are y = (-5/2)x + b
b can be any value, there are an infinite number of lines that fit the specs.