So you would use GEMDAS or PEMDAS
-8-1+4x2
-8-1+8
-9+8
-1
Perpendicular lines have the negative reciprocal slope, so the slope of your new line will be -1/4 and the current equation will be as follows:
y = -1/4x + b
(where b is the y intercept)
to find b, plug in point A and you'll get:
2 = -1/4(16) + b
2 = -4 + b
6 = b
the equation will be:
y = -1/4x + 6
