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3 years ago

Use quadratic regression to find

Mathematics

1 answer:

Verdich [7]3 years ago

8 0

Answer:

Step-by-step explanation:

y = ax² + bx + c

a( - 7)² + b( - 7) + c = 134 ⇔ 49a - 7b + c = 134 ......... (1)

a( - 3)² + b( - 3) + c = 10 ⇔ 9a - 3b + c = 10 ......... (2)

a(5)² + b(5) + c = 50 ⇔ 25a + 5b + c = 50 ......... (3)

(1) - (2)

40a - 4b = 124 ⇔ 10a - b = 31 ........... (4)

(3) - (2)

16a + 8b = 40 ⇔ 2a + b = 5 ........... (5)

(4) + (5)

12a = 36 ⇒ a = 3

2(3) + b = 5 ⇒ b = - 1

9(3) - 3( - 1) + c = 10 ⇒ c = - 20

y = 3x² - x - 20

y = [ 3 ] x² + [ - 1 ] x + [ - 20 ]

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Deacon wants to order DVDs. Each DVD costs $12.95, and he must pay a shipping and handling fee of $4.95 for the entire order. De

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Answer:

12.95a + 4.95 ≤ 75

Step-by-step explanation:

Given:

Cost of each DVD = $12.95

Total shipping fee = $4.95

Total amount as gift card = $75

Find;

Inequality

Computation:

Assume;

Number of DVD he purchase = a

So,

Total amount as gift card ≥ (Cost of each DVD)(Number of DVD he purchase ) + Total shipping fee

75 ≥ (12.95)(a) + 4.95

12.95a + 4.95 ≤ 75

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3 years ago

The length of a rectangle is 4 less than twice the width. If the perimeter of the rectangle is 130, find the length of the recta

Alchen [17]

Answer:

Let L be the length of the rectangle and w be the width of the rectangle.

"The lenght of a rectangle is one less than twice the width" means L=2W-1

Using perimeter formula of a rectangle which is P=2(L+W) you have:

P=2(L+W)

130=2(2W-1+W)

Solve equation above to find W

130=2(3W-1)

130=6W-2

130+2=6W

132=6W

W=22

From here you find L=2W-1=2x22-1=43

Only thing left is to find area A=LxW

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3 years ago

A marketing researcher wants to find a 96% confidence interval for the mean amount those visitors spend per person per day while

ki77a [65]

Answer:

$n=(\frac{2.054(12)}{4})^2 =37.97 \approx 38$

So then the minimum sample to ensure the condition given is n= 38

Step-by-step explanation:

Notation

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=12$ represent the population standard deviation

n represent the sample size

ME = 4 the margin of error desired

Solution to the problem

When we create a confidence interval for the mean the margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =4 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

The critical value for 96% of confidence interval now can be founded using the normal distribution. The significance is $\alpha=1-0.96 =0.04$ . And in excel we can use this formula to find it:"=-NORM.INV(0.02;0;1)", and we got $z_{\alpha/2}=2.054$ , replacing into formula (b) we got:

$n=(\frac{2.054(12)}{4})^2 =37.97 \approx 38$

So then the minimum sample to ensure the condition given is n= 38

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3 years ago

Luis wants to buy a skateboard that usually sells for $79.99. All merchandise is discounted by 12%. What is the total cost of th

DIA [1.3K]

Answer: $75.14

Step-by-step explanation:

to find out how much luis is saving with the discount you do

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and get around 9 ish dollars

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3 years ago

What is the measure of YB ?

BARSIC [14]

Answer:

YB = 12

Step-by-step explanation:

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7YB = 6 × 14 = 84 ( divide both sides by 7 )

YB = 12

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3 years ago