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3 years ago

Evaluate -3x3 - 4x for x = -1. 7 -1 1 PLSSSS HURRRY

Mathematics

1 answer:

enot [183]3 years ago

5 0

<em>When evaluating the function for x = -1 we get that the output equals 7</em>

<h2>Explanation:</h2>

In this exercise, we need to evaluate:

$-3x^3-4x \ for \ x = -1$

So let's call this a function $f(x)$ . So:

$f(x)=-3x^3-4x$

To evaluate $x=-1$ we need to substitute this value into the function, so:

$f(-1)=-3(-1)^3-4(-1) \\ \\ Solving: \\ \\ f(-1)=-3(-1)+4 \\ \\ Because: \\ \\ (-1)^3=-1 \ and \ -4(-1)=4 \\ \\ f(-1)=3+4 \\ \\ \boxed{f(-1)=7}$

Finally, <em>when evaluating the function for x = -1 we get that the output equals 7</em>

<h2>Learn more:</h2>

Roots of a polynomial function: brainly.com/question/1831722

#LearnWithBrainly

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If the null hypothesis is true in a chi-square test, discrepancies between observed and expected frequencies will tend to be

babymother [125]

Answer:

If the null hypothesis is true in a chi-square test, discrepancies between observed and expected frequencies will tend to be small enough to qualify as a common outcome.

Step-by-step explanation:

Here in this question, we want to state what will happen if the null hypothesis is true in a chi-square test.

If the null hypothesis is true in a chi-square test, discrepancies between observed and expected frequencies will tend to be small enough to qualify as a common outcome.

This is because at a higher level of discrepancies, there will be a strong evidence against the null. This means that it will be rare to find discrepancies if null was true.

In the question however, since the null is true, the discrepancies we will be expecting will thus be small and common.

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3 years ago

Cheddar cheese costs 7.50 for 1 kg Marie buys 200 grams of cheddar cheese how much does she pay

Varvara68 [4.7K]

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3 years ago

Read 2 more answers

The average of 8 numbers is 10. the average of 6 of the numbers is 12 what is the average of the other 2 numbers

omeli [17]

So, all 8 numbers added up would equal 80. and all 6 numbers added up would equal 72. The subtract them. 80-72 is 8. Then divide by 2 because there are 2 numbers. 8/2 is 4. (4 is your answer)

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4 years ago

My brother wants to estimate the proportion of Canadians who own their house.What sample size should be obtained if he wants the

AVprozaik [17]

Answer:

a) $n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

b) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

If solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Part a

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.9=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.675(1-0.675)}{(\frac{0.02}{1.64})^2}=1475.07$

And rounded up we have that n=1476

Part b

For this case since we don't have a prior estimate we can use $\hat p =0.5$

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.64})^2}=1681$

And rounded up we have that n=1681

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3 years ago

The claim that 40% of those persons who retired from an industrial job before the age of 60 would return to work if a suitable j

Bad White [126]

Answer:

The p-value of the test is of 0.1922 > 0.02, which means that there is not significant evidence to reject the null hypothesis, that is, there is not significant evidence to conclude that the proportion is of less than 40%.

Step-by-step explanation:

Test if the proportion is less than 40%:

At the null hypothesis, we test if the proportion is of at least 0.4, that is:

$H_0: p \geq 0.4$