Let $h(x)= 11- x^2$ .

(a) Find a point $P$ on the graph of $h(x)$ whose $x$-coordinate is $-5$.
$P = (-5,$ $)$

(b) Find two points $Q$ and $R$ on the graph of $h(x)$ whose $y$-coordinates are $-5$.
$Q = ($ $)$
$R = ($ $)$

(c) Let $p = 5$. Calculate the value of $h(p) - h(p-1)$.
$h(p) - h(p-1) =$