Explanation:
we start first by finding the gradient of the line
change in y/change in x
7-(-1)/3-7=8/-4
=-2
then for perpendicular lines m1m2=-1
therefore to find the gradient of that line
-2m2=-1
therefore m2=2
so therefore
y-5/x-3=2
so y-5=2x-6
y-2x=-1
in the form y= mx +c
then y=2x-1