## anonymous one year ago The function f(x) = −x2 + 44x − 384 models the daily profit, in dollars, a shop makes for selling donut combos, where x is the number of combos sold and f(x) is the amount of profit. Part A: Determine the vertex. What does this calculation mean in the context of the problem? (5 points) Part B: Determine the x-intercepts. What do these values mean in the context of the problem? (5 points) CAN YOU GVM THE ANSWERS PLEASE

1. anonymous

@jim_thompson5910

2. anonymous

@jim_thompson5910 ARE STILL THERE?

3. jim_thompson5910

what do you have so far?

4. anonymous

The function f(x) = −x2 + 44x − 384 models the daily profit, in dollars, a shop makes for selling donut combos, where x is the number of combos sold and f(x) is the amount of profit. Part A: Determine the vertex. What does this calculation mean in the context of the problem? (5 points) Part B: Determine the x-intercepts. What do these values mean in the context of the problem? (5 points)

5. jim_thompson5910

6. anonymous

yea can you help me its my last question?

7. jim_thompson5910

|dw:1436488305187:dw|

8. jim_thompson5910

|dw:1436488324499:dw|

9. jim_thompson5910

|dw:1436488354162:dw|

10. jim_thompson5910

oops I meant to say "a = -1"

11. anonymous

Part A: -1? Part B: 44? Part C: -384?

12. jim_thompson5910

no

13. anonymous

14. jim_thompson5910

a,b,c that i listed are the coefficients not the answers

15. jim_thompson5910

have you seen $\Large y = ax^2 + bx + c$ before?

16. jim_thompson5910

btw there is no part c

17. anonymous

OH YEA MY Bad, so i need to solve that problem?

18. jim_thompson5910

if a = -1 and b = 44 then what is $$\LARGE \frac{-b}{2a}$$ equal to?

19. anonymous

a=2 and b=2 ?

20. jim_thompson5910

$\Large \frac{-b}{2a} = \frac{-44}{2*(-1)} = ??$

21. anonymous

22?

22. jim_thompson5910

yes, so x = 22 is where the vertex is plug x = 22 into the original equation to find y

23. anonymous

so whats nexts? i need to find y?

24. jim_thompson5910

yes

25. jim_thompson5910

|dw:1436488910837:dw|

26. anonymous

-342?

27. jim_thompson5910

incorrect

28. jim_thompson5910

you should have gotten -1*(22)^2+44(22) - 384 = 100

29. jim_thompson5910

when x = 22, y = 100

30. jim_thompson5910

|dw:1436489230679:dw|

31. anonymous

oh ok, so whats next?

32. jim_thompson5910

What does this calculation mean in the context of the problem?  what does the vertex tell us?

33. anonymous

(22, 100)?

34. jim_thompson5910

yeah what does it mean in the real world? how does it translate into english?

35. jim_thompson5910

if you're stuck, what does x represent in this problem?

36. anonymous

twenty-two

37. jim_thompson5910

go back up at the top what does it say x represents? where x is the...

38. anonymous

x = 22 ?

39. jim_thompson5910

look at the instructions. It tells you what x means

40. jim_thompson5910

I don't want the number

41. jim_thompson5910

The function f(x) = −x2 + 44x − 384 models the daily profit, in dollars, a shop makes for selling donut combos, where x is _________ and f(x) is _____________.

42. anonymous

vertex?

43. jim_thompson5910

do you see what I mean? by asking to look at the instructions

44. jim_thompson5910

Fill in the blanks The function f(x) = −x2 + 44x − 384 models the daily profit, in dollars, a shop makes for selling donut combos, where x is _________ and f(x) is _____________.

45. jim_thompson5910

scroll to the very top of the page. You posted these instructions up there

46. anonymous

where x is the "number of combos sold" and f(x) is the amount of profit

47. jim_thompson5910

good

48. jim_thompson5910

when we say x = 22 and y = 100 that means when 22 combos are sold, the profit is 100 dollars

49. anonymous

oh

50. jim_thompson5910

(22,100) is the vertex at the highest point, so the most profit we can get is $100 and that happens when 22 combos are sold 51. jim_thompson5910 this is usually where managers want to aim 52. anonymous so that the answer for part A? 53. jim_thompson5910 yeah all so far for A 54. anonymous OR THAT only one part? 55. jim_thompson5910 we found the vertex and then gave an explanation of what it really means 56. anonymous ok thank you and for part B? 57. jim_thompson5910 solve 0 = -x^2 + 44x - 384 for x you can use technology (graphing) or the quadratic formula 58. anonymous Part A:(22,100) is the vertex at the highest point, so the most profit we can get is$100 and that happens when 22 combos are sold Part B:?

59. jim_thompson5910

part b) solve 0 = -x^2 + 44x - 384 for x you can use technology (graphing) or the quadratic formula

60. jim_thompson5910

desmos is a good graphing calculator https://www.desmos.com/calculator

61. jim_thompson5910

type in -x^2 + 44x - 384 then look for the x intercepts

62. anonymous

TYPE IN THE CALCULATOR?

63. jim_thompson5910

you see where the input box is?

64. anonymous

NO :/

65. jim_thompson5910

66. anonymous

OH OKAY WAIT LET ME SEE

67. anonymous

1?

68. jim_thompson5910

69. anonymous

OH IN THAT CALCULATOR I DONT KNOW HOW TO PUT X^2

70. jim_thompson5910

do you see the points (12,0) and (32,0) ?

71. anonymous

yes

72. jim_thompson5910

you just put in x^2 like you typed

73. jim_thompson5910

it understands that notation

74. jim_thompson5910

(12,0) and (32,0) are the x-intercepts x-intercept (12,0) when x = 12, the value of y is 0 so when 12 combos are sold, the profit is $0 x-intercept (32,0) when x = 32, the value of y is 0 so when 32 combos are sold, the profit is$0

75. jim_thompson5910

anything in between x = 12 and x = 32 means you'll have positive profits otherwise you will have 0 profit or negative profit (you lose money or owe it)

76. anonymous

lose?

77. jim_thompson5910

negative profit = you lost money ie you spent more than what you made

78. jim_thompson5910

example you send $10 but you only make$6 so you lost $4 (6-10 = -4) 79. anonymous oh yea 80. anonymous so? 81. jim_thompson5910 we're practically done with the problem 82. jim_thompson5910 Part B: Determine the x-intercepts. What do these values mean in the context of the problem? the x-intercepts are 12 and 32. As ordered pairs they are (12,0) and (32,0). They represent the points where the profit is$0. This is where you break even. You don't gain any money and you don't lose any money.

83. anonymous

so thats the asnwer for part B?

84. jim_thompson5910

more or less

85. anonymous

86. anonymous

LESS?

87. jim_thompson5910

huh? I don't know what you mean? I'm basically saying "yes"

88. anonymous

OH I THINK YOU ARE ASK ME IS MORE OR LESS

89. jim_thompson5910

ignore that portion

90. anonymous

SO WHAT WITH NEED TO DO NOW?

91. anonymous

WE*

92. jim_thompson5910

you're done, the problem is over

93. anonymous

SO WAIT THE ANSWER FOR PART B ITS: MORE OR LESS?

94. jim_thompson5910

no

95. jim_thompson5910

I already gave it to you. Just go back and re-read it

96. anonymous

the x-intercepts are 12 and 32. As ordered pairs they are (12,0) and (32,0). They represent the points where the profit is \$0. This is where you break even. You don't gain any money and you don't lose any money.

97. anonymous

???

98. jim_thompson5910

yeah just put that into your own words. Hopefully you understand what I mean?

99. anonymous

IN my own words? i dont know

100. anonymous

@jim_thompson5910 ???

101. jim_thompson5910

you can do it

102. anonymous

103. anonymous

:(

104. jim_thompson5910

Give it your best shot. Just be confident.

105. anonymous

so wait i need to write the answer in my own?

106. anonymous

with my own letters?

107. jim_thompson5910

yes

108. anonymous

thankss for you help