Consider the function $f(x)=5-4x^{2}on$ the interval $-4,4.$ Find the average $or$ mean slope $of$ the

function $on$ this interval, $i.e.$

$\frac{f(4)-f(-4)}{4-(-4)}=$

$By$ the Mean Value Theorem, $we$ know there exists $acin$ the open interval $(-4,4)$ such that $f^{\text{'}}(c)is$ equal

$to$ this mean slope. For this problem, there $is$ only one $c$ that works. Find $it.$