Question 301983
The slope of any line perpendicular to the line = -1/m 
where m is the gradient of the line. 

Formular for finding gradient using two points = [Y,2 - Y,1]/[X,2-X,1]

Gradient = [5-3]/[4-(-2)]
= 2/6
=1/3

Therefore, the slope of the prependicular line = -3