You can clearly see that the white shapes are positive while the black shapes are negative. You can determine this because all (except F) claim that the 6 shapes are negative.
To make it easier, use elimination. It's definitely not J because you are not subtracting -6, but adding (as seen in the equation.) It is not F because 2(3)=6 when the equation needs -6.
So it is either G or H...
H claims that 12x+3+(-6) is what the model symbolizes; but this is incorrect. Unless x is a decimal, you can not have the large shape as the "purest" form (so to speak.) The "purest" state you can go in this model is a cube/square which=1.
Therefore, "G Jamey modeled 12 + 3x + (-6) and it is equivalent to 12x-3" is the correct answer.
