We can write the following equations:

X + 2Y -2Z = 5

2Y -2Z = 4

X + 4Z = -7

Multiplying the second equation by -1 and adding to the first equation, it gives X = 1

Then, replacing the value of X in the third equation, we obtain Z = -2

Finally, replacing the value of Z in the first equation, Y = 0

Therefore ,

1 + 0 -2 = -1