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3 years ago

Can some one help explain this

Mathematics

2 answers:

Ber [7]3 years ago

5 0

Answer:

$4( {x}^{2} - 1) - ( {x}^{2} - 8x - 5)$

$4 {x}^{2} - 4 - {x}^{2} + 8x + 5$

$3 {x}^{2} + 8x + 1$

cluponka [151]3 years ago

4 0

Bananas snajeswakkwwkwwwmwmmwwwnwnnw

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Which property is illistarted by the statement (4+6.1)+7=4+(6.1+7)

Marat540 [252]

Answer:

Commutative Property of Addition.

Step-by-step explanation:

The Commutative Property of Addition states that no matter what order you add the numbers, the outcome (answer) will all be the same.

7 0

3 years ago

The equation y=6.72(1.014) x models the world population y , in billions of people, x years after the year 2000 . Find the year

Marizza181 [45]

the population will reach 8 billion by 2012 ,as calculated by properties of logarithm.

<h3>What is Logarithm?</h3>

The opposite of exponentiation is the logarithm.
This indicates that the exponent to which a fixed number, base b, must be raised in order to obtain a specific number x, is represented by the logarithm of that number.
A number's natural logarithm is its logarithm to the base of the transcendental and irrational number e, which is roughly equivalent to 2.718281828459.

Given:

y = 6.72 ( $1.014^x$ ), where

y = population in billions
x = time in years

To find: Year when population is 8 billion, i.e., y = 8.

Finding:

8 = 6.72 ( $1.014^x$ )

=> $\frac{8}{6.72}= ( 1.014^x)$

Taking log on both sides

=> $log(\frac{8}{6.72})= log( 1.014^x)$

=> log(1.19) = x (log 1.014) (as $log_b(a)^m = m (log_b(a))$ )

=> $\frac{log(1.19)}{log (1.014)}$ = x

=> x = $\frac{0.0755}{0.006}$

=> x = 12.58

Hence, the population will reach 8 billion by 2012 ,as calculated by properties of logarithm.

To learn more about logarithms, refer to the link: brainly.com/question/25710806

#SPJ4

5 0

1 year ago

34% of 65. Do not round!!! pls help

anastassius [24]

Answer:

22.1

Step-by-step explanation:

If we put 65 over 100 and x over 34 and do cross multiplication, we see that 65 times 34 is 2,210. Dividing 100 from both sides of the equation, we divide 100 from x and 100 from 2,210. We are left with X = 22.1

6 0

3 years ago

Read 2 more answers

The distribution of SAT II Math scores is approximately normal with mean 660 and standard deviation 90. The probability that 100

gayaneshka [121]

Using the <em>normal distribution and the central limit theorem</em>, it is found that there is a 0.1335 = 13.35% probability that 100 randomly selected students will have a mean SAT II Math score greater than 670.

<h3>Normal Probability Distribution</h3>

In a normal distribution with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

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

It 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, which is the percentile of X.

By the Central Limit Theorem, the sampling distribution of sample means of size n has standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

In this problem:

The mean is of 660, hence $\mu = 660$ .

The standard deviation is of 90, hence $\sigma = 90$ .

A sample of 100 is taken, hence $n = 100, s = \frac{90}{\sqrt{100}} = 9$ .

The probability that 100 randomly selected students will have a mean SAT II Math score greater than 670 is <u>1 subtracted by the p-value of Z when X = 670</u>, hence:

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

By the Central Limit Theorem

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