word problem involving quadratic equation..NEED HELP

[deederz]

You need to supply information to an event coordinator about an upcoming event. You need to supply that person with a progected ticket sales number. You provide the ticket manager with a quadratic equation that models the expexted number of ticket sales each day. tickets=-.02^2+12x+11. with x=1 is the day tickets go on sale.
This has several question
1.does graph go up or dowm? I know that the graph will open downwards because the "a" value in the equation is negative.
2. describe what happens to the ticket sales as time passes? I think they would start out selling well and then increase as it gets closer to the time of the event.
3. Use equadritic equation to determine the last day tickets will be sold.
4.Will tickets peak or be at a low during the middle of the sale? How do you know?
5.After how many days will the peak or low occur?
6. how many tickets will be sold on that day?
7.What is the point of vertex? I kind of know how to get that part
8.How does that number relate to answers 5 and 6?
9. How many solutions are there to the equation?
10 What do the solutions represent, if there is one that does not makes sense, why or why not?

 

[burakaltr]

You need to supply information to an event coordinator about an upcoming event. You need to supply that person with a progected ticket sales number. You provide the ticket manager with a quadratic equation that models the expexted number of ticket sales each day. tickets=-.02^2+12x+11. with x=1 is the day tickets go on sale.
This has several question
1.does graph go up or dowm? I know that the graph will open downwards because the "a" value in the equation is negative.
2. describe what happens to the ticket sales as time passes? I think they would start out selling well and then increase as it gets closer to the time of the event.
3. Use equadritic equation to determine the last day tickets will be sold.
4.Will tickets peak or be at a low during the middle of the sale? How do you know?
5.After how many days will the peak or low occur?
6. how many tickets will be sold on that day?
7.What is the point of vertex? I kind of know how to get that part
8.How does that number relate to answers 5 and 6?
9. How many solutions are there to the equation?
10 What do the solutions represent, if there is one that does not makes sense, why or why not?

Any graph that is A x**2 + B x +C = y

if A pos, looks up and vice versa

-b/2a = x of Vertex

f(-b/2a)= y of vertex

y= 0---> x axis intersections

if dy/dx = 2 A X + B is positive goes up and vice versa

 

[Deleted member 4993]

You need to supply information to an event coordinator about an upcoming event. You need to supply that person with a progected ticket sales number. You provide the ticket manager with a quadratic equation that models the expexted number of ticket sales each day. tickets=-.02x^2+12x+11. with x=1 is the day tickets go on sale.
This has several question

1.does graph go up or dowm?

Wthout a given domain, that question does not make sense. It is an equation of "parabola". Given enough space - it goes both up and down.

I know that the graph will open downwards because the "a" value in the equation is negative.

Perhaps you meant the graph "opens" up or down. If that is what you meant - than your interpretation is correct. This graph (parabola) has a maximum at x= 300.

2. describe what happens to the ticket sales as time passes? I think they would start out selling well and then increase as it gets closer to the time of the event.

The slope of the tangent decreases as x increases - that means the ticket sell will be "brisk" in the begining and it will slow down.

3. Use equadritic equation to determine the last day tickets will be sold.

Find the roots (zeros) of the equation.

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

Plot the function and look at its maxima/minima and zeros to visualize the answers.

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

Plot the function and look at its maxima/minima and zeros to visualize the answers.

6. how many tickets will be sold on that day?

Plot the function and look at its maxima/minima and zeros to visualize the answers.

7.What is the point of vertex? I kind of know how to get that part
8.How does that number relate to answers 5 and 6? - Since you know (7), you should know this.
9. How many solutions are there to the equation?

This is a strange question - there are infinite solutions to the equation - the number of points on the parabola.

10 What do the solutions represent, if there is one that does not makes sense, why or why not?

.

 

[deederz]

well this just confused me even more. I did the equadratic equation -b(+_) sqrt b^2-4ac over 2a and ended up with -12+sqrt 135.2/.4 and -12sqrt - 135.2/.4. I really can not figure this out...

 

[deederz]

i also did -b/2a and came up with -30, but am not sure what to do with that number

 

[mmm4444bot]

well this just confused me even more.

Sorry about that, but you're kinda confusing me, too.



I did the equadratic equation -b(+_) sqrt b^2-4ac over 2a and ended up with -12+sqrt 135.2/.4 and -12sqrt - 135.2/.4.

When you get to this stage of using the Quadratic Formula, you're not done. Use a scientific calculator to find the square root, and divide it by 0.4 and then do the arithmetic with -12 to arrive at decimal numbers for each result.

When I simplify your results above, I get x = -41.0689 or x = 17.0689.

These are not the correct roots.

Please show your work, so that we can see what you're doing wrongly.

 

[Deleted member 4993]

i also did -b/2a and came up with -30, but am not sure what to do with that number

I thought you knew about the vertex of a parabola.

Please plot the function in your graphic calculator (or computer) and look!!!

 

[lookagain]

Any graph that is A x**2 + B x +C = y

if A pos, looks up and vice versa

-b/2a = x of Vertex

f(-b/2a)= y of vertex

y= 0---> x axis intersections

if dy/dx = 2 A X + B is positive goes up and vice versa

It's the Order of Operations.

Enclose the denominator with grouping symbols:

-b/(2a) = x and

f(-b/(2a)) = y

 

[lookagain]

well this just confused me even more. I
did the equadratic equation -b(+_) sqrt b^2-4ac over 2a and
ended up with -12+sqrt 135.2/.4 and -12sqrt - 135.2/.4.
I really can not figure this out...

deederz,

you must have grouping symbols around the numerator, the denominator**,
and the radicand.
Also, the subtraction sign for the second root is to go immediately
to the left of "sqrt."

And you would expect to get the wrong answers with your set-up.

The word in front of "equation" is spelled "quadratic."
You are stating a formula, not an equation.

Type this amended portion:

"...quadratic formula (-b +/- sqrt(b^2 - 4ac))/(2a) and ended up with

(-12 + sqrt(135.2))/.4 and (-12 - sqrt(135.2))/.4,"

but in this, I am not necessarily agreeing with the values you used in

the quadratic formula.


** They're needed as in (2a) for the quadratic formula before
the values are substituted.