6 Simplify. \[ \frac{4 x^{2}-16 x}{x^{2}-16} \]

To simplify the expression \(\frac{4 x^{2}-16 x}{x^{2}-16}\), we start by factoring the numerator and the denominator. The numerator can be factored as \(4x(x - 4)\) and the denominator can be factored as \((x - 4)(x + 4)\). Now, rewriting the expression gives us: \[ \frac{4x(x - 4)}{(x - 4)(x + 4)} \] Next, we can cancel out the common factor \((x - 4)\) from the numerator and the denominator (assuming \(x \neq 4\) to avoid division by zero). This simplifies our expression to: \[ \frac{4x}{x + 4} \quad (x \neq 4) \] So the final simplified form is: \[ \frac{4x}{x + 4} \]