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F point = (- 6, 3)
Perpendicular to (1, 0) (0, -3)
1.- Find the slope of the perpendicular line
m = (-3 - 0) / (0 - 1)
m = -3/-1
m = 3
3.- Find the slope of the new line. Perpendicular the the original line.
m = -1/3
4.- Find the equation of the new line
y - y1 = m(x - x1)
y - 3 = -1/3 (x + 6)
y - 3 = -1/3 x - 6/3
y = -1/3x - 2 + 3
y = -1/3x + 1
5.- Result
y = -1/3x + 1 in the form slope y-intercept