Question 26197
Sounds as though you know the slope of the given line is 1/2
So the slope of the line perpendicular to it is -2.
If m=-2 and the line passes through (-2,-1) you get:
-1=(-2)(-2)+b
b=-5
Equation of the line is y=-2x-5
Standard form is ax+by=c
Therefore rewrite your equation as 2x+y=-5 to put it 
in standard form.

Cheers
Stan H.