Question

An expression is shown below:

f(x) = 4x2 + 8x − 5

Part A: What are the x-intercepts of the graph of f(x)? Show your work. (2 points)

Part B: Is the vertex of the graph of f(x) going to be a maximum or minimum? What are the coordinates of the vertex? Justify your answers and show your work. (3 points)

Part C: What are the steps you would use to graph f(x)? Justify that you can use the answers obtained in Part A and Part B to draw the graph. (5 points)

Answer 1

@Hero

Answer 2

After he helps can you please leave your question up. I wanna try it

Answer 3

sure

Answer 4

The x intercepts are the values of x that occur when f(x) = 0.

Answer 5

ok

Answer 6

So simply set f(x) = 0, then solve for x.

Answer 7

By the way, for a quadratic function of the form \(f(x) = ax^2 + bx + c\) if \(a < 0\) then the vertex of the function will have a maximum value. If \(a > 0\) then the vertex will have a minimum value.

Answer 8

x intercept = (1 over 2 ,0) and (-5 over 2, 0)

Answer 9

Cool, but you should show your work for it.

Answer 10

I don't want to do the work, I just want to check it.

Answer 11

i know i have been showing u the full thing i just want to make sure its right before i show u the whole thing

Answer 12

Yes, they are correct.

Answer 13

The reason to show the steps is so that I know you actually attempted to solve it on your own as opposed to just graphing to get the points.

Answer 14

TIGGS IS BACK

Answer 15

T_T i graphed cause it twas hard

Answer 16

i need help im confused with this once cause so many things give different answers

Answer 17

AHA. So when you attempted to solve it, how did you set it up to solve it?

Answer 18

well f(x)=4x^2 + 8x - 5

Answer 19

Yep, that was the given problem. But surely there is something you can do with it that I mentioned earlier.

Answer 20

.......................

Answer 21

urmmm i am really bad at the f(x) = ax^2+bx+c

Answer 22

The first step was to set f(x) = 0, so you should have had:
\(0 = 4x^2 + 8x - 5\)
as your first step.

Answer 23

ok so 4x^2+8x-5 then you split them up right

Answer 24

You're covered Brennah? Or could I assist you?

Answer 25

im waiting for hero to get back and see

Answer 26

Then you FACTOR them, yes. I don't know what you mean by SPLITing.

Answer 27

like make them into 2

Answer 28

(2x-1) (2x+5) would be it when its factored

Answer 29

@Hero

Answer 30

Please show your work.

Answer 31

I don't know why you are not showing your work for these. If you don't intend to show your point, I don't see any reason to post just the answer. You could get that from anywhere. A calculator of some sort. Showing your work is the only proof you can provide that you actually did the work.

Answer 32

(4x^2-2x) + (10x-5)
=2x(2x-1)+5(2x-1)
=(2x-1) (2x+5)

Answer 33

Looks right. Gotta go. BBL

Answer 34

ok but be back soon cause i still havent been able to answer any of the question and its getting late

Answer 35

@Shadow

Answer 36

You have it factored, so set it to zero and solve for x

Answer 37

easier said than done

Answer 38

can u help me figure that out cause i need to have my work shown and im not gewd at that

Answer 39

\[(2x-1) (2x+5) = 0\]


\[2x - 1 = 0\]
\[2x + 5 = 0\]

Solve for x

Answer 40

\(\color{#0cbb34}{\text{Originally Posted by}}\) @AnimeGhoul8863
x intercept = (1 over 2 ,0) and (-5 over 2, 0)
\(\color{#0cbb34}{\text{End of Quote}}\)
i had the answer i just get confused getting it

Answer 41

What do you mean?

Answer 42

i need to show my work so im confused how u go from 2x−1=0

2x+5=0 to 1 over 2 ,0) and (-5 over 2, 0)

Answer 43

my brain freezes at these moments and i can never figure it out

Answer 44

Did you get those numbers? Or did someone give them to you?

Answer 45

in the beginning i got them from a calculator and they hero was helping me find out how to find them by showing my work

Answer 46

\[(2x - 1)(2x + 5) = 0\]

\[2x - 1 = 0\]
\[2x = 1\]
\[x = \frac{ 1 }{ 2}\]

\[2x + 5 = 0\]
\[2x = -5\]
\[x = - \frac{ 5 }{ 2 }\]

Answer 47

OHHHHHHHH

Answer 48

so if thats the answer to part A lets move to part B

Answer 49

Part B: Is the vertex of the graph of f(x) going to be a maximum or minimum? What are the coordinates of the vertex? Justify your answers and show your work. (3 points)

Answer 50

Just graph it. The maximum is when the vertex is highest point of the graph, and the minimum is when the vertex is the lowest point of the graph.

Answer 51

(-1,-9)

Answer 52

the vertex is minimum because the graph shows it going into the negatives which make it the lowest point in the graph

Answer 53

@Shadow

Answer 54

am i correct?

Answer 55

Correct vertex and correct that it's the minimum, but not because it's "going into the negative." Just say it's because it's the lowest point.

Answer 56

ok and last one Part C: What are the steps you would use to graph f(x)? Justify that you can use the answers obtained in Part A and Part B to draw the graph. (5 points)

Answer 57

@Hero

Answer 58

Part C: when you graph if you use the vertex and x intercept it will give you your function

Answer 59

^correct or should i change

Answer 60

The answer is probably lurking in your text somewhere.

Answer 61

what do u mean

Answer 62

In your textbook or online book notes.

Answer 63

urrmmmmmmmmm

Answer 64

What I mean is, when I was in school, even if I needed help with something, I didn't have access to the help I needed. Had to figure it out on my own. Our role isn't to help you with every single question.

Answer 65

its to help me with the questions i ask but ok ill just try to do it myself even tho this is the reason im here thx for the help u gave