Question

HI anyone care to help me with a algebra problem off line?

Answer 1

sure what kind?

Answer 2

-_- this is gonna take awhile

Answer 3

I haven't read all of the questions yet, but they are all pretty straightforward, for the first one you can really just describe the function. Or what you expect from it, that's all I would recommend you to do because the remaining questions should answer it mathematically.

Answer 4

a.

Insert various numbers for x and then see what happens, on the first day, not many tickets will be sold, second day, only a bit more, the longer the time passes by the more tickets will be sold until a certain day, on this day there will be a maximum of tickets sold, then the amount of tickets sold will decrease again until one fine day, nobody bothers anymore to see the show.

Answer 5

okay so far?

Answer 6

lol yup im still tryna figure this out.

Answer 7

hmm well @milo2012 , my post above is just a description of what will happen, you could easily plug in the numbers yourself, if you have a calculator near you and see what happens. The question a) just requires you to describe what is going on.

Answer 8

XD

Answer 9

@wasiqqs help the kid out :D

Answer 10

@wasiqss lol
Still waking up...

Answer 11

lol yea we need all the help we can get

Answer 12

@rebeccaskell94 im tired :P

Answer 13

Yes

Answer 14

lol Are you in Alg I or II?

Answer 15

lol

Answer 16

;( life sucks okay let me keep working

Answer 17

b) -ax^2+bx+c, there is a negative sign in front of the coefficient, therefore has a maximum, the lower end is opened.

Answer 18

@milo2012 what level of Algebra are you in?

Answer 19

oh gawd. my head is spinning. i need a drink

Answer 20

*hands kia a drink* carry on

Answer 21

@lalaly you're super smart can you help?!

Answer 22

where is the problem if I might ask?

Answer 23

there are a bunch of questions up there, they are all related to three basic formulas though, all for quadratic equation (the topic I guess). If that topic is a problem in general, then it's hard to help though (at least for me)

Answer 24

yes, I saw that already and replied to two questions already, just not sure if that helped somehow

Answer 25

*drinks slowly* thanks becca!

Answer 26

yea i got letter "B' but sill letters C through I and number 2 & 3 to answer.

Answer 27

c)

Compute the discriminant

\[ D= b^2-4ac = 69.8\] since it is positive > 0 there are two solutions to the general quadratic equation.

Answer 28

d)

Application of the quadratic formula will give you both results, they are just not very nice to look at:

\[ \frac{-b \pm \sqrt{b^2-4ac}}{2a}
\]

You should get

\[x_1=-1.693299 \\x_2=19.193299 \]

These are the days where are zero tickets sold.

Answer 29

check the answers for yourself again to verify that there are no careless mistakes involved.

Answer 30

Question e) It asks if the tickets will be at a low or at a high during the middle term, judging by your teachers hint, we care about the days starting from x=1 to x=19 (roughly , 19, exact result by the quadratic equation)

So we care what the average sale value is in these days.

Answer 31

1+19 = 20, divided by 2 gives the average = 10, after ten days (x)

You get

\[ f(10)=43 \] tickets, so that's a lot for this function.

Answer 32

therefore peak.

Answer 33

yup

Answer 34

okay

Answer 35

in fact it answers f and g already too.

Answer 36

it's just not the exact answer, exact answer is required at h, if you reread them.

Answer 37

yes, I don't find the questions very good myself to be honest with you, let me repost them here so I don't have to scroll up and down all the time.

e. Will tickets peak or be at a low during the middle of the sale? How do you know?

f. After how many days will the peak or low occur?

g. How many tickets will be sold on the day when the peak or low occurs?

h. What is the point of the vertex? How does this number relate to your answers in parts f and g?

Answer 38

ok

Answer 39

E was asking for an average, like we know from d that they will sell tickets for approximately 19 days, at the 19th day they will sell zero tickets. So they are asking us in e) for a rough assumption, if they will sell a lot of tickets during the middle of the sale or not.

Answer 40

If we count day 1 as first day, and day 19 as the last day, we can calculate the average which is 10, at the tenth day they sell 43 tickets (insert that into the function to prove)

Answer 41

f) we have answered now too, approximately after 10 days, (all that is approximately, add this!) because they don't ask for EXACT answers, the exact answers they want at h)

Answer 42

and it's a peak, not a low, a low wouldn't make sense in general if you want to add that, the low is at the end of the show season, not in the middle. This function doesn't give the perfect description of how a band concert is visited, but it makes some sense after all.

Answer 43

correct, g we have answered already, if you enter x=10 days into your equation you obtain 43 tickets sold.

Answer 44

I think so, some of this question require an EXACT result, some just want you to make an educated guess and see how it turns out approximately, they want to give you a feeling of how the quadratic equations (quadratic polynomial) work and what they tell you.

Answer 45

oh okay

Answer 46

h. What is the point of the vertex? How does this number relate to your answers in parts f and g?

i. What do the solutions represent? Is there a solution that does not make sense? If so, in what ways does the solution not make sense?

Answer 47

So h) is an exact question now again, you have to use the formula for the vertex which is

\[ v = \frac{-b}{2a}=8.75\] so after 8.75 days we sell the MOST tickets during the entire season.

Answer 48

If you plug that into your function you get

\[f(8.75)=43.625\ \text {tickets}\]

Answer 49

yes, and now you can add for letter H what you observe, as you see, the results we have done previous, not sure where it started but I guess it was e) f) g) were rough approximations, what we did at h) was a correct mathematical calculation.

So that tells you that our approximation was pretty good, in fact it's better then the original (accurate/exact) result we derived in h), because you cannot sell any half tickets (43.625 tickets makes no sense, that's 43 and a half ticket, nobody buys a half ticket, also a part to the answer in i)

Answer 50

and finally, this tells you that the vertex is located in between the roots of your function.

Answer 51

hmm, well the last question asks for what the solutions represent and if some of them don't make sense.

Answer 52

there are two who don't really make sense, the first one is the accurate sell value of the tickets, which is 43.625, that's just not a good result, because nobody buys .625 of a ticket, you buy a whole ticket, or no ticket at all.

Also at d) we have obtained that a zero of our function is somewhere around -1 days, that means at x=-1 we sell no tickets, that is trivial, because that's before the performance starts.

Your teacher tells you from day x=1 , so it is obviously unnecessary to say that in the past x= negative value, before the event started, you haven't sold any tickets.

Answer 53

and I think that's really all there is to say to this question.

Answer 54

okay wow you walking it thru step by step with me helped me understand everything that was weird, are you able to help me with number 2 & 3.

Answer 55

can you repost them?

Answer 56

3 should be x^2-8x+14?

Answer 57

ok

Answer 58

Ok lets say that x is one number, and x-8 is the other number.

Answer 59

or you can also make it x+8 would maybe better.

Answer 60

so you can set up the following quadratic equation for example

\[f(x)= x^2-8x\]

Answer 61

so the vertex of this equation is x=4, this would be one number, and therefore the other number would be 12

Answer 62

and if you don't want to use a quadratic equation as they might require you can say that two numbers, in integers, like 1 and 9 have the difference of 8, and there product is 9

Answer 63

but I believe they want to limit you on the quadratic equation

Answer 64

can you follow that?

Answer 65

so @milo2012 , my internet crashed, but I am back

Answer 66

was the last step I performed clear to you?

Answer 67

yes exactly, I assume they don't want you to use whole and even numbers and numbers except zero, otherwise you could cheat here

Answer 68

do you have 3? It's the same as 2 though, just need to figure out the vertex I guess.
And yes I am here during the week.

Answer 69

the lowest value is the vertex

\[ -\frac{b}{2a}=4\]

After four days, they reach their lowest value and it's

\[f(4)=-2\]

Answer 70

yep it is.

Answer 71

we will talk before your final then (-:

Answer 72

you are welcome! take care.