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3 years ago

What is the value of the sum?

1 answer:

6 0

-7/9+2/3
Change 2/3 to 6/9 becajse we need to have the same denominator to able to calculate the sum, so
-7/9+6/9
=-1/9. As a result, D and E are the final answer. Hope it help!

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Subtract<br> (2x²+5) - (4x - 3)

Ivahew [28]

Answer:

x = -1

Step-by-step explanation:

1.1 Pull out like factors :

-2x - 2 = -2 • (x + 1)

2.1 Solve : -2 = 0

x = -1

3 0

4 years ago

Read 2 more answers

Two different sizes of square metal duct are joined by a piece that is a frustum of a pyramid. Find the lateral surface area, if

Allisa [31]

Answer:

288 in²

Step-by-step explanation:

The formula used to solve this question is :

Lateral Surface Area = s( P1 + P2)

Where s = slant height = 2 inches

P1 and P2 = Perimeter of the bases

Perimeter of base 1 = 4 × length of the end of the small square

4 × 17 inches = 68 inches

Perimeter of base 2 = 4 × length of the end of the large square

4 × 19 inches = 76 inches

Lateral Surface Area = 2 × (68 + 76)

= 2 × 144

= 288 in²

8 0

3 years ago

List two equivalent numbers to 0.50

ad-work [718]

1/2, 4/8. If in decimal form, you can also do 0.5 or 0.500

8 0

3 years ago

12-1/5r = 2r +1 solve for r

levacccp [35]

Answer:

r=5

Step-by-step explanation:

1.simplify both sides of the equation.

2.substract 2r from both sides.

3.substract 12 from both sides.

4.multiply both sides by 5/(11)

5. your answer will be 5.

r=5

6 0

3 years ago

Read 2 more answers

You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard devia

Arturiano [62]

Answer:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (3)

$n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791$

So the answer for this case would be n=791 rounded up to the nearest integer

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (2)

And on this case we have that ME =+5 and we are interested in order to find the value of n, if we solve n from equation (2) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (3)

$n=(\frac{2.58(54.5)}{5})^2 =790.846 \approx 791$

So the answer for this case would be n=791 rounded up to the nearest integer

4 0

3 years ago