Answer:
y = - 2x
Explanation:
The equation of a line in slope- intercept form is
y = mx + c ( m is the slope and c the y- intercept )
Given
2y = x - 3 ( divide the terms by 2 )
y = 
 x -
 x - 
 ← in slope- intercept form
 ← in slope- intercept form
with slope m = 

Given a line with slope m then the slope of a line perpendicular to it is
 = -
 = - 
 = -
 = - 
 = - 2 , then
 = - 2 , then
y = - 2x + c ← is the partial equation
To find c, substitute (- 1, 2) into the partial equation
2 = 2 + c ⇒ c = 2 - 2 = 0
y = - 2x ← equation of the perpendicular line