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2 years ago

Solve x2 + 8x − 3 = 0 using the completing-the-square method

1 answer:

4 0

Hello :
x²+8x-3=0
(x² +2(4)x +4²) -4² -3 = 0
(x+4)²-19 = 0
(x+4)² = 19
x+4 = √19 or x+4 = - √19
x = √19 - 4 or x = -√19 - 4

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Doss [256]

Answer:

The proportion of children in this age range between 70 lbs and 85 lbs is of 0.9306.

Step-by-step explanation:

When the distribution is normal, we use 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.

A study suggested that children between the ages of 6 and 11 in the US have an average weightof 74 lbs, with a standard deviation of 2.7 lbs.

This means that $\mu = 74, \sigma = 2.7$

What proportion of childrenin this age range between 70 lbs and 85 lbs.

This is the pvalue of Z when X = 85 subtracted by the pvalue of Z when X = 70. So

X = 85

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

$Z = \frac{85 - 74}{2.7}$

$Z = 4.07$

$Z = 4.07$ has a pvalue of 1

X = 70

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

$Z = \frac{70 - 74}{2.7}$

$Z = -1.48$

$Z = -1.48$ has a pvalue of 0.0694

1 - 0.0694 = 0.9306

The proportion of children in this age range between 70 lbs and 85 lbs is of 0.9306.

7 0

2 years ago

Many poker games start with each player being dealt five cards, called the player's "hand". Remember, there are 52 cards in a st

jek_recluse [69]

Answer:

The number of different possible poker hands is found by counting the number of ways that 5 cards can be selected from 52 cards, where the order is not important. It is a combination, so we use c n r

Step-by-step explanation:

The possible number of the poker hands is probably . C 52 5= 52!/5!x47!= 2598960

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2 years ago

Line Q is parallel to the line represented by the equation 5x – 4y = 10. Line Q passes through the point (12, –7). Which linear

marysya [2.9K]

A, plug in 12 for x and -7 for y to get you’re answer

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2 years ago

Brandon is baking cookies for a school bake sale. If he can make 2 dozen cookies in 23 minutes which is a reasonable estimate of

madreJ [45]

It would be around 138 minutes which is 2 hrs and 18 min so it would be C).