First we have to find the slope of 2x + 4y = -7
Solve for y by subtracting 2x and then dividing by 4 to get
y = (-7 - 2x)/4 or y = -1/2x - 7/4
This shows the slope as -1/2
The perpendicular slope is the negative reciprocal of this or 2/1 = 2
So the perpendicular line equation will be y = 2x + b
To find b plug in the given point (-3,-2) so -2 = 2(-3) + b
Solving for b gives b = 4
Now you can write the full equation y = 2x + 4