Select the correct answer.

A parabola can be drawn given a focus of (-9, -7) and a directrix of x = 9. Write

Slav-nsk [51]

Check the picture below, so the parabola looks more or less like so, with a vertex at (0 , -7), let's recall the vertex is half-way between the focus point and the directrix.

so this horizontal parabola opens up to the left-hand-side, meaning that the "P" distance is a negative value.

$\textit{horizontal parabola vertex form with focus point distance} \\\\ 4p(x- h)=(y- k)^2 \qquad \begin{cases} \stackrel{vertex}{(h,k)}\qquad \stackrel{focus~point}{(h+p,k)}\qquad \stackrel{directrix}{x=h-p}\\\\ p=\textit{distance from vertex to }\\ \qquad \textit{ focus or directrix}\\\\ \stackrel{"p"~is~negative}{op ens~\supset}\qquad \stackrel{"p"~is~positive}{op ens~\subset} \end{cases} \\\\[-0.35em] \rule{34em}{0.25pt}$

$\begin{cases} h=0\\ k=-7\\ p=-9 \end{cases}\implies 4(-9)(x-0)~~ = ~~[y-(-7)]^2 \\\\\\ -36x=(y+7)^2\implies x=-\cfrac{1}{36}(y+7)^2$

4 0

2 years ago

If Kye can rollerblade 1.5 miles in 8 minutes how many miles does he rollerblade in 1 minute

mixer [17]

Answer:

0.1875 miles

Step-by-step explanation:

3 0

3 years ago

What affect does h = -2 have on the parent function y=1/x ?

kherson [118]

Graph moves 2 units up Vertical stretch by a factor of |-2| Graph moves 2 units down Graph moves 2 units to the left

4 0

3 years ago

Riverside elementary school is holding a schoolwide election to choose a color. 5/8 of the votes were for blue. 5/9 of the remai

sleet_krkn [62]

Answer:

There were 180 votes for blue.

Step-by-step explanation:

Given:

Riverside elementary school is holding a schoolwide election to choose a color. 5/8 of the votes were for blue. 5/9 of the remaining votes were for green and the remaining 48 votes were for red.

Now, to find the votes for blue.

Let the total votes be $x.$