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alina1380 [7]
3 years ago
13

align="absmiddle" class="latex-formula">

completing the square
Mathematics
1 answer:
Brrunno [24]3 years ago
8 0

Answer:

<h3>x = 3/2 ± √(61/20)</h3>

Step-by-step explanation:

5x² - 15x - 4 = 0

Add 4 to both sides.

5x² - 15x = 4

The coefficient of 5x² is 5, divide both sides by 5.

x² - 3x = 4/5

The coefficient of -3x is -3. Let b=-3.

Then we need to add (b/2)^2=9/4 to both sides to complete the square.

Add 9/4 to both sides.

x² - 3x + 9/4 = 61/20

Factor left side.

(x-3/2)² = 61/20

Take square root of both sides.

x-3/2 = ± √(61/20)

Add 3/2 to both sides.

x = 3/2 ± √(61/20)

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The amount of soft drink in a bottle is a Normal random variable. Suppose that in 7% of the bottles containing this soft drink t
WITCHER [35]

Answer:

The mean is 15.93 ounces and the standard deviation is 0.29 ounces.

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

7% of the bottles containing this soft drink there are less than 15.5 ounces

This means that when X = 15.5, Z has a pvalue of 0.07. So when X = 15.5, Z = -1.475.

Z = \frac{X - \mu}{\sigma}

-1.475 = \frac{15.5 - \mu}{\sigma}

15.5 - \mu = -1.475\sigma

\mu = 15.5 + 1.475\sigma

10% of them there are more than 16.3 ounces.

This means that when X = 16.3, Z has a pvalue of 1-0.1 = 0.9. So when X = 16.3, Z = 1.28.

Z = \frac{X - \mu}{\sigma}

1.28 = \frac{16.3 - \mu}{\sigma}

16.3 - \mu = 1.28\sigma

\mu = 16.3 – 1.28\sigma

From above

\mu = 15.5 + 1.475\sigma

So

15.5 + 1.475\sigma = 16.3 – 1.28\sigma

2.755\sigma = 0.8

\sigma = \frac{0.8}{2.755}

\sigma = 0.29

The mean is

\mu = 15.5 + 1.475\sigma = 15.5 + 1.475*0.29 = 15.93

The mean is 15.93 ounces and the standard deviation is 0.29 ounces.

6 0
2 years ago
martin is ordering dvds online. each dvd is priced at $8.50. the wedsite also charges a flat fee of $5.00 for shipping and handl
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Y=8.50x+5.00
56=y
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56=8.50x+5.00
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51=8.50x
÷8.5 ÷8.5

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7 0
3 years ago
Cindy bought 4 packets of onion seeds. Each packet contained 12 seeds. She planted 1 packet of the seeds, and 8 seeds sprouted.
olga55 [171]

Answer:

B because 8 seeds from pack 1. u do 8 times 3 other packs which is 24 So in between 20-30 seeds will sprout

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3 years ago
Is 10 pounds greater or 10 kilograms
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Pounds  is more if you do the math
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If the original price was $58 and the new price is $66 what is the percent change
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I believe the answer is 65%. i'm not sure
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