constant: z = 1 - x - y (therefore they are all equal to one, so they are a fraction/decimal and, in this case, a probability. this is for a game theory class).
x - y + z = v (v stands for value of the game)
x + 2y + z = v
-x - y +2z = v
x - y - z = v
-x + 2y - z = v
x + y + 2z = v
basically solve for all the variables (x, y, z, and v(alue) if you can). thank you.