The 1 side and the 2 side of the dice represent the questions he answers correctly. The 3, 4, 5, and 6 sides of the dice represents the questions he answers incorrectly.
I think the answer would just be 12a because -9a? And +9a? Would cancel out and the -10 and +10 would cancel out so all that is left is the 12a
The answer is C. 3x+5= 5x -8
I guess the only way to use subtraction is to take the total area of the grid and subtract it by the total area around the figure. So it since it is a 10 by 10 grid, it would be 100 (since 10*10=100) minus the area around the shape.
