Answer:
Isolate the "d" variable by adding 6 to the left side of the equation, cancelling it out to 0. Subsequently, you would also add 6 to the right side of the equation to complete the transition.
-3d = 12
Next, divide by -3 to get the variable "d" all by itself.
d = -4
We can prove this equation is true by plugging -4 back into the original equation: -3(-4) - 6 = 6
Thus, we get 6 = 6, so this equation is correct.