Step-by-step explanation:
To find the value of \( x + y + z \), we'll first substitute the given expressions for \( X \), \( Y \), and \( Z \) into the expression for \( x + y + z \):
\[ x + y + z = (2x + 3y - 4z) + (x - 3y + 4z) + (2x + y - z) \]
Now, let's simplify the expression by combining like terms:
\[ x + y + z = (2x + x + 2x) + (3y - 3y + y) + (-4z + 4z - z) \]
\[ x + y + z = 5x + y - z \]
So, \( x + y + z = 5x + y - z \). We cannot simplify it further without knowing specific values for \( x \), \( y \), and \( z \).
