Well, looking at the graph, notice, its vertex is at 0,9, and it passes through the points -3,0 and 3,0, so hmm let's use 3,0, to get the equation of f(x)

$\bf ~~~~~~\textit{parabola vertex form}
\\\\
\begin{array}{llll}
\boxed{y=a(x- h)^2+ k}\\\\
x=a(y- k)^2+ h
\end{array}
\qquad\qquad
vertex~~(\stackrel{}{ h},\stackrel{}{ k})\\\\
-------------------------------$

$\bf vertex~(0,9)~
\begin{cases}
h=0\\
k=9
\end{cases}\implies y=a(x-0)^2+9
\\\\\\
\textit{we also know that }
\begin{cases}
x=3\\
y=0
\end{cases}\implies 0=a(3-0)^2+9
\\\\\\
-9=9a\implies \cfrac{-9}{9}=a\implies -1=a\quad thus\quad \boxed{y=-x^2+9}
\\\\\\
\left. \cfrac{dy}{dx}=-2x \right|_{x=3}\implies -6$

3 0

4 years ago

Read 2 more answers

Explain how to find the constant rate of change from the verbal description below.

Oksanka [162]

Answer:

62miles/1hr

Step-by-step explanation:

In order to get the rate of change I divided 124 miles by 2 hours to get 62 miles.

3 0

3 years ago