Given line : y = -x - 6
Comparing it with y = mx + c
slope of line, m = -1
So the slope of the line perpendicular to it will be = -1/m = -1/(-1) = 1
So the perpendicular line will be of the form: y = x + k
where k is a constant.
It passes through (-9,-4)
Thus
-4 = (-9) + k
=> k = (-4) + 9
=> k = 5
Thus, equation of perpendicular line is y = x + 5
