## adl_thoo Group Title Since opening night, attendance at Play A has increased steadily, while attendance at Play B first rose and then fell. Equations modeling the daily attendance y at each play are shown below, where x is the number of days since opening night. On what day(s) was the attendance the same at both plays? What was the attendance? Play A: y = 15x + 76 Play B: y = –x^2 + 36x – 4 one year ago one year ago

1. Luigi0210 Group Title

You could set both equations equal to each other or graph and see where they intersect.

2. smokeydabear Group Title

Yes, all you are trying to do is find where the two graphs intersect, so setting the two equal to each other will give you the answer.

is that my quickest way? i have 40 questions. and im only on 13.

4. Luigi0210 Group Title

Yes, listen to Miss Bear :P

5. smokeydabear Group Title

Judging from your previous problems, I think your teacher is emphasizing the quadratic formula, so yes you will have to go through it once again =P

UGH , it confuses me badly.

7. Luigi0210 Group Title

I could give the solution if that'll help speed things along for you?

8. smokeydabear Group Title

It confuses you? What part of it confuses you?

everything.

The attendance was the same on day 5. The attendance was 151 at both plays on that day. The attendance was the same on day 16. The attendance was 316 at both plays on that day. The attendance was the same on days 5 and 16. The attendance at both plays on those days was 151 and 316 respectively. The attendance was never the same at both plays. these are my answer choices.

11. smokeydabear Group Title

It is a strategy used to figure out what value x has to be to make the quadratic equation equal to 0. Does that help?

12. smokeydabear Group Title

Honestly I am trying my hardest not to solve the problem, both for your practice and to fuel my laziness xD Luigi, would you like to solve it?

13. Luigi0210 Group Title

Do you want a graph to help visual the equations?

it doesnt matter. thats fine.

15. Luigi0210 Group Title

It's kinda big sorry about the size

16. smokeydabear Group Title

Now that you see the intersecting points, you have to realize something about this problem. This is a problem that is using months for the x axis. Tell me why there is in reality only one solution to this problem?

okat, hmmm...

18. smokeydabear Group Title

Don't overthink it, this is more of a common sense thing. Also, you could see the reason using the attendance number as well (y axis).

19. Luigi0210 Group Title

If I solved it right, and I probably didn't but the exact answer would be $\frac{ -21+/-\sqrt{761} }{ 2}$

20. Luigi0210 Group Title

But it would be the positive answer because you can't have negative units

would it be C? The attendance was the same on days 5 and 16. The attendance at both plays on those days was 151 and 316 respectively.

22. smokeydabear Group Title

Look at what Luigi wrote. You can't have a negative number of people, or negative number of months for that matter.

23. Luigi0210 Group Title

The points of intersection is (3.2931, 125.397)

exactly. so answer C would be correct, right?

25. smokeydabear Group Title

I may just be looking at the graph wrong, but that shouldn't be it. C is telling you that there are two solutions to this problem. What Luigi and I were trying to tell you is that there is only one valid answer here.

26. smokeydabear Group Title

Are you understanding what I'm saying?

27. Luigi0210 Group Title

So what the intersection points are say is that there are 125 people on day 3

28. Luigi0210 Group Title

Are you understanding this or are getting more confused? :l

more confused.

30. Luigi0210 Group Title

I'm sorry ^_^' what specifically is confusing you?

31. smokeydabear Group Title

Okay think about it like this. If you were to take exactly what the graph told you as the solutions of the problem, you would have a negative number for something that can't be negative.

a lot. idk why i think it is C .. idk ): is it B ?

33. smokeydabear Group Title

C would make sense if you were just trying to find solutions to the raw graphs, but we are looking at a real life scenario.

exactly... so, would it change my answer to B ?

35. smokeydabear Group Title

I feel like it's A, because the point on the graph looks more like (5, 151) than (16, 316)

36. Luigi0210 Group Title

You're probably thinking of it as a general graph like bear is saying. But think of it this way. When dealing with real life, is it possible to have negative audience and/or negative days?

no.. so, a ,, is correct?

38. Luigi0210 Group Title

And what are the solution choices? I must of missed them ._.

39. smokeydabear Group Title

It was (5, 151) for A, and (16, 316) for B. C said that both are true, and D said neither are true.

yeah, what she said . ^_*

41. Luigi0210 Group Title

I'd say D.

42. Luigi0210 Group Title

But yet again she is the smart one here so..

43. smokeydabear Group Title

But what is bothering me is why they would consider (16, 316) as a possible solution. It's not even the negative solution... it's not anywhere on the graph xD

44. smokeydabear Group Title

Maybe the graph is wrong...

ahhh , im confused. @primeralph , what would your input be on this question ?

46. Luigi0210 Group Title

Oops, bear is right I used the wrong equation

47. Luigi0210 Group Title

it is (5, 151)

ohh goodness. so my answer is A ?

49. Luigi0210 Group Title

I'm so sorry for messing this up D:

50. smokeydabear Group Title

Oh okay, but I just plugged the B coordinates into the original equations, and it worked.

51. smokeydabear Group Title

Let me try for A next.

52. Luigi0210 Group Title

I'm so sorry for messing this up D:

53. primeralph Group Title

Imma just say, equate the two y's. Find an x. Then plug into any one of the equations.

its fine.. & okay, ive gotten so confused. idk what to do :(

55. primeralph Group Title

56. smokeydabear Group Title

Okay I just confirmed that it is B

57. Luigi0210 Group Title

And no you were right the answer is A or whatever the points are

58. smokeydabear Group Title

The graph threw me off, I just went brute force and plugged everything in, and only (16, 316) worked.

so its B ?

60. smokeydabear Group Title

But aren't they equal at (16, 316)? Luigi, can you plug in the points into the equations to check?

61. Luigi0210 Group Title

As it turns out both work :/

62. Luigi0210 Group Title

So adl was right after all

63. smokeydabear Group Title

Oh look, my calculator was messing with me. Yes both work.

64. smokeydabear Group Title

My calculator never did like order of operations -.-

65. primeralph Group Title

|dw:1368580026141:dw|

66. primeralph Group Title

yo, was I too late?

67. Luigi0210 Group Title

Naw :P

noo . im still figuring this out.

69. smokeydabear Group Title

We were struggling for a long time and eventually got it, but your input helps reassure us, or me at least ^^

70. primeralph Group Title

plug in both 5 and 16 separately into eq A. That gives the number of people

Sooo , wasit A B or C ?

72. Luigi0210 Group Title

My stupidity has made this a bit harder than it needed to be

73. Luigi0210 Group Title

and C

74. smokeydabear Group Title

It is C, because both work.

75. smokeydabear Group Title

That was extremely stressful...

lol, itss, yay !! :D thanks guys.

77. primeralph Group Title

I don't know what the options are. It's really not stressful at all

veryyyy !

79. primeralph Group Title

errr.............I knew what to do.............

shoot, i didnt.

81. Luigi0210 Group Title

It was just because I graphed the wrong equations :l

82. smokeydabear Group Title

It was only confusing because of Luigi's graph! >:0 But it's okay Luigi, I still wuv you <3

83. primeralph Group Title

so what did you get?

84. Luigi0210 Group Title

Next time don't listen to me :P

its okay guys :) we got it as The attendance was the same on days 5 and 16. The attendance at both plays on those days was 151 and 316 respectively.

86. primeralph Group Title

yeah