The slope of a line passing through the points `(x_1, y_1)` and `(x_2, y_2)` is S = `(y_2 - y_1)/(x_2 - x_1)` . The product of the slope of two perpendicular lines is equal to -1.

If a line passes through the points (6, 8) and (8, 6) its slope is `(6 - 8)/(8 - 6) = -1` .

The slope of a line perpendicular to this line is `(-1)/(-1)` = 1. If this line passes through the point (0, 8) the equation of the line is `(y - 8)/(x - 0) = 1`

=> y - 8 = x

=> x - y + 8 = 0

The equation of the required line is x - y + 8 = 0