Answer :
I don’t know how to explain it so I am just giving the equation
12=-4(-6x-3x)
Divide both sides by 4
12/4=-4(-6x-3x)/4
3=-4(-6x-3x)/4
3=-(-6x-3x)
3=9x
9x/9 = 3/9
Divide both sides by 9
x=1/3
12=-4(-6x-3x)
Divide both sides by 4
12/4=-4(-6x-3x)/4
3=-4(-6x-3x)/4
3=-(-6x-3x)
3=9x
9x/9 = 3/9
Divide both sides by 9
x=1/3