Calculate the slope of the line through and using the slope formula.
Then derive an expression in that represents the slope of the line through and using the same slope formula.
Find the negative reciprocal of either of the slopes. Since the slopes of perpendicular lines are negative reciprocal of each other, set one slope equal to the negative reciprocal of the other and then solve the resulting equation for
John
My calculator said it, I believe it, that settles it