Slope-intercept form of a line is given by the expression:
y=mx+b
where,
m=slope
To find the slope of the line represented by the equation given, we have to isolate y and find m.
Then,
-12x-4y=-2
4y=-12x+2
y=-12/4x+2/4
y=-3x+1/2
So, the slope in this case would be -3