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3 years ago

-4(2z+6)-12=4. HAAAAAAAAALP. please include explanation.

Mathematics

2 answers:

DiKsa [7]3 years ago

4 0

Answer:

Z = -5

Step-by-step explanation:

1) multiply bracket

-4 x 2z = - 8z

-4 x 6 = - 24

2) put back into equation

-8z - 24 - 12 =4

3) collect like terms

-8z - 36 =4

4) get z alone

-8z - 36=4

+36 +36

-8z = 40

5) find z

-8z =40

divide both sides by - 8

Z= - 5

Phoenix [80]3 years ago

3 0

Answer:

Step-by-step explanation:

-4(2z+6)-12 = 4

=> -8z - 24 - 12 = 4

=> -8z = 4 + 12 + 24

=> -8z = 40

$= > z = \frac{40}{ - 8}$

=> z = - 5 (Ans)

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Explain why the expression below always has the same value, no matter what number other than zero you choose for p.

Natasha2012 [34]

Answer and explanation:

The expression P-2P+3P-4P cannot have the same values for different values of P. Let us illustrate this by substituting different values of P in the expression:

If P= 2

Substitute P=2 in the expression

2-2×2+3×2-4×2

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If P= 3

Substitute P=3 in the expression

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If P = 1

Substitute P=1 in the expression

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8 0

3 years ago

At 95% confidence, how large a sample should be taken to obtain a margin of error of 0.03 for the estimation of a population pro

Gnom [1K]

Answer:

A sample of 1068 is needed.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

At 95% confidence, how large a sample should be taken to obtain a margin of error of 0.03 for the estimation of a population proportion?

We need a sample of n.

n is found when M = 0.03.

We have no prior estimate of $\pi$ , so we use the worst case scenario, which is $\pi = 0.5$

Then

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.03 = 1.96\sqrt{\frac{0.5*0.5}{n}}$

$0.03\sqrt{n} = 1.96*0.5$

$\sqrt{n} = \frac{1.96*0.5}{0.03}$

$(\sqrt{n})^{2} = (\frac{1.96*0.5}{0.03})^{2}$

$n = 1067.11$

Rounding up

A sample of 1068 is needed.

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3 years ago

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Step-by-step explanation:

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