The parabola above is the graph of y= -x^2 + k, where k is a constant.

If AB=10, what is the slope of AP?A) 2

B) 5/2

C) 5

D) 10

E) 20

You know the parabola’s axis of symmetry is the *y*-axis, so you know that points A and B are (–5, 0) and (5, 0), respectively. Let’s use one of those to solve for *k*:

0 = –(5^2) + *k*

0 = –25 + *k*

25 =* k*

Now that you know *k*, you can use what you know about graph translation to see quickly that point *P* is (0, 25). So find the slope between (–5, 0) and (0, 25):