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3 years ago

What are the solutions to. x^2 - x - 20 = 0

Mathematics

1 answer:

nignag [31]3 years ago

3 0

Step-by-step explanation:

x² - x - 20 = 0

x² - (5-4) x - 20 = 0 

x² - 5x + 4x -20 = 0

x ( x - 5) + 4 ( x - 5) = 0

(x - 5) (x+ 4) = 0

Either. 

x - 5 = 0

x = 5

Or, 

x + 4 = 0 

x = -4

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I am a 3-digit number. I am a even number. The sum of all my digits together is 12. In my numbers there are only two different d

beks73 [17]

Answer:

228

Step-by-step explanation:

228 = 3 digits

2 + 2 + 8 = 12

228 = 2 different digits (2 and 8)

2 ≤ 2 < 8

6 0

3 years ago

Suppose babies born after a gestation period of 32 to 35 weeks have a mean weight of 2800 grams and a standard deviation of 900

ipn [44]

Answer:

The 34 week gestation's period baby weighs 0.11 standard deviations below the mean.

The 41 week gestation's period baby weighs 0.24 standard deviations below the mean.

A. The baby born in week 40 does since its z-score is smaller.

Step-by-step explanation:

Normal model problems can be solved by the zscore formula.

On a normaly distributed set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a value X is given by:

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

The zscore represents how many standard deviations the value of X is above or below the mean[/tex]\mu[/tex]. Whoever has the lower z-score weighs relatively less.

Find the corresponding z-scores.

Babies born after a gestation period of 32 to 35 weeks have a mean weight of 2800 grams and a standard deviation of 900 grams. A 34-week gestation period baby weighs 2700 grams.

Here, we have $\mu = 2800, \sigma = 900, X = 2700$ .

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

$Z = \frac{2700 - 2800}{900}$

$Z = -0.11$

A negative z-score indicates that the value is below the mean.

So, the 34 week gestation's period baby weighs 0.11 standard deviations below the mean.

Babies born after a gestations period of 40 weeks have a mean weight of 3400 grams and a standard deviation of 425 grams. A 40-week gestation period baby weighs 3300 grams.

Here, we have $\mu = 3400, \sigma = 425, X = 3300$