4) \( x y+y z-w x+4-3 x y-z y-4 w z-4 \)

To solve the expression \( x y + y z - w x + 4 - 3 x y - z y - 4 w z - 4 \), we can begin by combining like terms. First, we collect the terms involving \(x y\): - \(x y - 3 x y = -2 x y\) Next, let's address the \(z y\) and \(w z\) terms: - \(y z - z y = 0\) (they cancel each other out) - Thus, we are left with \(-w x - 4 w z\). Now, we can summarize all this: \[ -2 x y - w x - 4 w z + 4 - 4 = -2 x y - w x - 4 w z \] The simplified expression is: \[ -2 x y - w x - 4 w z \] With this expression, you're left with a clear formula featuring \(x\), \(y\), \(z\), and \(w\)!