1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ZanzabumX [31]
3 years ago
6

PLEASE HELP WILL GIVE BRAINLY!!!!!!!!!What is the vertex of the graph of the function f(x) = x2 + 8x − 2 ?

Mathematics
2 answers:
vovangra [49]3 years ago
7 0
<h3>Answer: D.  (-4, -18)</h3>

===================================================

Explanation:

A graph is a nice addition (and it will likely help us see the vertex directly), but it isn't necessary because we can use the equation given to us. Though I recommend using a graphing calculator to confirm the answer.

The original function is the same as y = 1x^2+8x + (-2). We see that it is in the form y = ax^2+bx+c where

a = 1

b = 8

c = -2

Use the values of 'a' and b to get the value of h, which is the x coordinate of the vertex.

h = -b/(2a)

h = -8/(2*1)

h = -4

The x coordinate of the vertex is x = -4. Plug this into the original equation to get

f(x) = x^2+8x-2

f(-4) = (-4)^2 + 8(-4) - 2

f(-4) = -18

Plugging x = -4 into f(x) leads to y = -18. The point (-4, -18) is on the parabola. Furthermore, this is the vertex (h,k)

------------

Alternatively, you can complete the square as shown below

y = x^2 + 8x - 2

y = (x^2 + 8x) - 2

y = (x^2 + 8x + 0) - 2

y = (x^2 + 8x + 16 - 16) - 2

y = (x^2 + 8x + 16) - 16 - 2

y = (x+4)^2 - 18

y = 1(x+4)^2 - 18

y = 1(x-(-4))^2 - 18

The last equation is in the form y = a(x-h)^2 + k with (h,k) = (-4,-18) being the vertex. The 16 is the result of taking half of 8 and squaring that result. We have 16-16 = 0 to make sure that we don't change the equation and keep things balanced. This is the same as adding 16 to both sides. All of this is done so we can end up with the (x+4)^2 perfect square portion.You can expand out (x+4)^2 - 18 and you should get x^2+8x-2 again.

mafiozo [28]3 years ago
7 0
D is the answer

Because you need to rewrite in vertex form and use this form to find the vertex (h,k)

Which should get you to

(-4,-18)
You might be interested in
How do I do numbers 12 to 14?
NARA [144]

Answer:

  12.  1 second, 35 ft; 2 seconds, 32 ft

  13.  (t, y) = (1.4 seconds, 37.6 feet)

  14.  37.6 ft; the vertex is the highest point

Step-by-step explanation:

12. You have properly answered question 12.

After 1 second, the height is 35 feet; after 2 seconds, it is 32 feet.

__

13. My method of choice is to plot the graph on a graphing calculator and let it show me the coordinates of the vertex when I highlight that point. (See attached.) The vertex is ...

  (t, y) = (1.4, 37.6)

__

14. The graph is a graph of height when the object is launched with a vertical velocity of 45 ft/s. So, the maximum of the graph will correspond to the maximum height of the object. The vertex is that maximum point, and its y-coordinate is that maximum height.

The maximum height is 37.6 feet.

8 0
3 years ago
PLEASE I NEED HELP, ASAP!!<br><br> –4(5–2a)+3(a–4)=6(2–a)–5a
creativ13 [48]
The answer to this question  is a=2   

8 0
3 years ago
Read 2 more answers
What does the word "eliminate" most likely mean, as it is used in this
stiks02 [169]

Answer:

This is Exclude because they didn’t want them anymore or didn’t want to hire them or include them in a conversation.

5 0
3 years ago
For an irrational number x = 3 + 2√2 , find out what will be the nature of the number x + 1 /
Wittaler [7]

It will be irrational. The sum of any irrational and rational number will ALWAYS result in a irrational answer. Khan Academy has a video on this if you want to watch it.
3 0
3 years ago
A file that is 289 MB is being downloaded. If the download it is 14.1% complete, how many megabytes have been downloaded?
Greeley [361]

Answer:

40

Step-by-step explanation:

5 0
1 year ago
Other questions:
  • 7. Brad put 10 crickets in his pet After one day Brad's lizard had eaten of the crickets he had put in the cage. By the end of t
    14·1 answer
  • Cam y'all please help me with this one
    6·1 answer
  • What statement describes the relationship between ∆ XYZ and ∆ X'Y'Z'?
    8·1 answer
  • Find the values of k so that the slope of he line joining (5,k) and (6,k^2) is 30.
    15·1 answer
  • If the diameter of a circle is 7/2, what is the radius, circumference in terms of pi and what is the approximate circumference?
    11·2 answers
  • Find the GCF of each set of numbers.<br><br>12, 30, 72<br>Lesson 2 My​
    11·1 answer
  • Which property yields Step 2
    10·1 answer
  • Complete the table for the equation you wrote in Exercise 6.
    8·1 answer
  • Which pair of functions are inverse of each other
    7·1 answer
  • On his lunch break, Calvin purchases a burger and a drink. The total order is $8.50, of which $1.08 is tax. How much was Calvin'
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!