The instructions begin with "Find the equation of the line ... " and should be included in your post.
This new line is perp. to the line y - 3x = 8, or y = 3x + 8. Slope is 3.
Thus, a line perp to this one would have the slope -1/3.
In point-slope form: y-2 = (-1/3)(x-[-10]), or y - 2 = (-1/3)(x+10) (answer)