You plot the point of the focus and the directrix on the graph to determine where the parabola opens.
We are provided the general forms of parabola according to its opening if:
it opens upward: (x - h)<span>² = 4a(y - k)
</span>it opens downward: (x - h)<span>² = -4a(y - k)
where "h" and "k" are the coordinates of the vertex, and "a" is the focal length from the focus to the vertex.
As you plot, the directrix y = 9 is a horizontal line, and the focus at (0,-9) is below that directrix. So, it means that the parabola opens downward (and not upward because the parabola must not touch to the directrix).</span> Next, identity the vertex (h,k). Note that the vertex is the midpoint between the focus and the point of the directrix. So the vertex is (0,0). Then, the focal length "a" is 9.
Hence, the equation is
(x - 0)<span>² = -4(9)(y - 0)
x</span><span>² = -36y</span>
Answer:
5. D
6. C
Step-by-step explanation:
<u>Question 5</u>
Lets plug in values of x and y into each equation to see which one works for the entire data set...
y=2x-4
1) Plug in -7 as x and -18 as y:
-18=2(-7)-4
2) Multiply:
-18=-14-4
3) Subtract:
-18=-18
The answers are the same, therefore the correct answer to question 5 is equation D. Keep in mind, you want to check ever single pair of points to make sure it works for all of them, I'm just not going to list that as it would make this answer a lot longer for no reason.
<u>Question 6:</u>
We know that the cost for the boat is $25 as a base price, and also costs an additional $1.30 per day for fuel.
The correct equation is C=25+1.30d, because we are adding 1.3 every single day.
As with simple linear regression, we desire the residuals to:
- Have constant variance.
- Have a mean close to 0.
<h3>What is a simple linear regression?</h3>
It should be noted that a simple linear regression simply means a model that describes the relationship between a dependent variable and an independent variable.
In this case, as with simple linear regression, we desire the residuals to have constant variance and have a mean close to 0.
Learn more about regression on:
brainly.com/question/25987747
Answer: its 4. Look at the graph, x is horizontal and y is vertical (first go sideways then go up.) if coordinates are x,y then first go sideways when looking for x. they give you x. 7. then we go up. the graph intersects 7 at 4, therefore the coords are 7, 4 and your y coordinate is 4.
Step-by-step explanation: