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2 years ago

Please help i dont understand!!!

Mathematics

1 answer:

Hitman42 [59]2 years ago

8 0

The answer is
$\\ {a}^{ - \frac{ 13}{5} } \\ or \\ a {}^{ - 2.6}$

good luck

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Matt is 15 years younger than Angela. 9 years ago, Angela's age was 2 times Matt's age. How old is Matt now?

Nuetrik [128]

Matt would be now 15

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3 years ago

On a coordinate plane, a line goes through (negative 3, 0) and (0, negative 6).

shusha [124]

Answer:

B. (1,-8)

Step-by-step explanation:

Slope of the first one:

(-6-0)/(0--3) = -6/3 = -2

y = -2x - 6

3y + 30 = 6x

y + 10 = 2x

-2x - 6 + 10 = 2x

4 = 4x

x = 1

y = -2(1) - 6

y = -8

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3 years ago

Read 2 more answers

Which of the following sets shows all the numbers from the set {1, 2.5, 3, 4.5, 5} that make the inequality 3a + 4 ≥ 13 true?

zmey [24]

3(1)+4≥ 13
7≥ 13
No

3(2.5)+4≥ 13
11.5≥ 13
No

3(3)+4≥ 13
13≥ 13
Yes

{3, 4.5, 5}

3 0

3 years ago

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Suppose a 90% confidence interval for the mean salary of college graduates in a town in Mississippi is given by [$38,737, $50,46

JulsSmile [24]

Answer:

a. The point estimate was of $44,600.

b. The sample size was of 16.

Step-by-step explanation:

Confidence interval concepts:

A confidence interval has two bounds, a lower bound and an upper bound.

A confidence interval is symmetric, which means that the point estimate used is the mid point between these two bounds, that is, the mean of the two bounds.

The margin of error is the difference between the two bounds, divided by 2.

a. What is the point estimate of the mean salary for all college graduates in this town?

Mean of the bounds, so:

(38737+50463)/2 = 44600.

The point estimate was of $44,600.

b. Determine the sample size used for the analysis.

First we need to find the margin of error, so:

$M = \frac{50463-38737}{2} = 5863$

Relating the margin of error with the sample size:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.9}{2} = 0.05$

Now, we have to find z in the Z-table as such z has a p-value of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.05 = 0.95$ , so Z = 1.64.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

For this problem, we have that $\sigma = 14300, M = 5863$ . So

$M = z\frac{\sigma}{\sqrt{n}}$

$5863 = 1.645\frac{14300}{\sqrt{n}}$

$5863\sqrt{n} = 1.645*14300$

$\sqrt{n} = \frac{1.645*14300}{5863}$

$(\sqrt{n})^2 = (\frac{1.645*14300}{5863})^2$

$n = 16$

The sample size was of 16.

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2 years ago

If the diameter of the circle is above 20mm what is the area

Phoenix [80]

Answer:

The area would be 314.16 mm squared

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3 years ago