The answer is -40 because if you get rid of the negative sign and add instead of subtract... you get 40 so its like adding in the opposite direction.
2 is the slope so the slope perpendicular to that is -1/2 (negative reciprocal)
-5=-1/2(9) 9*-1/2=-4.5 and -4.5 - 0.5 = -5 so the equation for the line is y=-1/2x -0.5
1 meter = 1000 millimeters
so, 5 meters = 5*1000 = 5000 millimeters
and 6000 millimeters = 6000 / 1000 = 6 meters
