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2 years ago

PLEASE HELP W MATHHHH

Mathematics

2 answers:

IRISSAK [1]2 years ago

8 0

Answer:

(15m^2 + 5)

Step-by-step explanation:

(m2 - 3m + 19 ) + (2m2 + m) + (4m2 - 7) + (2m2 + m) + (4m2 - 7) + (2m2 + m)

15m2 + 0m + 5

=> 15m^2 + 5

Aleks [24]2 years ago

7 0

Answer:

try adding all the sides up

Step-by-step explanation:

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The following graph shows Barry's monthly phone bill and the number of minutes used. About how many minutes did Barry consume if

hram777 [196]

Answer:

About 27.5 minutes

Step-by-step explanation:

When looking at the graph, you can see that the red line intersects about 27.5 minutes with $55.

6 0

3 years ago

A miners' cage of mass 420 kg contains 3 miners of total mass 280 kg. The cage

svp [43]

Answer:

5817 Newtons.

Step-by-step explanation:

Total mass of the cage + the miners = 700 Kg which is a downward force of 700g N.

The net downward force = 700g - T where T is the tension (force) in the cable. The g = acceleration due to gravity = 9.81 m s-2.

We calculate the acceleration of the cage by using an equation of motion:

Distance = ut + 1/2 a t^2 where u = initial velocity , t = time and a = acceleration:

75 = 0(t) + 1/2 a (10^2)

50a = 75

a = 1.5 m s-2.

So using Newtons second law of motion

Force = mass * acceleration:

700*9.81 - T = 700 * 1.5

T = 700 * 9.81 - 700*1.5

= 5817 N.

8 0

3 years ago

Find the function's range. Enter your answer in interval notation

DerKrebs [107]

Answer:

its subject matter about eco

Step-by-step explanation:

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6 0

3 years ago

The length of a pen is 5 more than its width.The perimeter is 26 m.Find the length and the width.

meriva

P=2l+2w

Since it is given that P=26m, length is 5 more than its width (w+5), we'll work it out in the perimeter formula.

26=2(w+5)+2w
26=2w+10+2w
26=4w+10
4w=26-10
4w=16
w=4

Thus the width is 4m. Let's find the length.

l=w+5
l=4+5
l=9

The length of a pen is 9m.

4 0

3 years ago

Read 2 more answers

In 2002, the mean age of an inmate on death row was 40.7 years with a standard deviation of 9.6 years according to the U.S. Depa

marissa [1.9K]

Answer:

The 95% confidence interval for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Step-by-step explanation:

The confidence interval of the mean is given by the next formula:

$\\ \overline{x} \pm z_{1-\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$ [1]

We already know (according to the U.S. Department of Justice):

The (population) standard deviation for this case (mean age of an inmate on death row) has a standard deviation of 9.6 years ( $\\ \sigma = 9.6$ years).
The number of observations for the sample taken is $\\ n = 32$ .
The sample mean, $\\ \overline{x} = 38.9$ years.

For $\\ z_{1-\frac{\alpha}{2}}$ , we have that $\\ \alpha = 0.05$ . That is, the level of significance $\\ \alpha$ is 1 - 0.95 = 0.05. In this case, then, we have that the z-score corresponding to this case is:

$\\ z_{1-\frac{\alpha}{2}} = z_{1-\frac{0.05}{2}} = z_{1-0.025} = z_{0.975}$

Consulting a cumulative standard normal table, available on the Internet or in Statistics books, to find the z-score associated to the probability of, $\\ P(z$ , we have that $\\ z = 1.96$ .

Notice that we supposed that the sample is from a population that follows a normal distribution. However, we also have a value for n > 30, and we already know that for this result the sampling distribution for the sample means follows, approximately, a normal distribution with mean, $\\ \mu$ , and standard deviation, $\\ \sigma_{\overline{x}} = \frac{\sigma}{\sqrt{n}}$ .

Having all this information, we can proceed to answer the question.

Constructing the 95% confidence interval for the current mean age of death-row inmates

To construct the 95% confidence interval, we already know that this interval is given by [1]:

$\\ \overline{x} \pm z_{1-\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$

That is, we have:

$\\ \overline{x} = 38.9$ years.

$\\ z_{1-\frac{\alpha}{2}} = 1.96$

$\\ \sigma = 9.6$ years.

$\\ n = 32$

Then

$\\ 38.9 \pm 1.96*\frac{9.6}{\sqrt{32}}$

$\\ 38.9 \pm 1.96*\frac{9.6}{5.656854}$

$\\ 38.9 \pm 1.96*1.697056$

$\\ 38.9 \pm 3.326229$

Therefore, the Upper and Lower limits of the interval are:

Upper limit:

$\\ 38.9 + 3.326229$

$\\ 42.226229 \approx 42.23$ years.

Lower limit:

$\\ 38.9 - 3.326229$

$\\ 35.573771 \approx 35.57$ years.

In sum, the 95% confidence interval for the current mean age of death-row inmates is between 42.23 years and 35.57 years.

Notice that the "mean age of an inmate on death row was 40.7 years in 2002", and this value is between the limits of the 95% confidence interval obtained. So, according to the random sample under study, it seems that this mean age has not changed.

7 0

3 years ago