✡ When subtracting negatives, your going to do the same thing has subtracting without negatives.

- - Hope this helps! - -
I think the answer would be 1932 tiles cubed, I think you might need help from someone else though, sorry.
12x-5+85=128.......12x+80=128......12x+80-80=128-80....12x=48...... divide both sides by 12 to get x=4. Now most people do not complete solving for the missing value....12(4)-5=43 degrees
I think -1,2 or something else I’m not sureee sorry hope it’s gets answered