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2 years ago

Determine the factors of the expression x^2 - 9

Mathematics

1 answer:

Anuta_ua [19.1K]2 years ago

5 0

Answer:

Step-by-step explanation:

The answer is B.

Use the sum-product pattern

2+3−3−9

Common factor from the two pairs

2+3−3−9x2+3x−3x−9

(+3)−3(+3)

Rewrite in factored form

(+3)−3(+3)

Solution:

(−3)(+3)

‘Hope it Helps!

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A dog breeder would like to know how many Dalmatian puppies are typically born in a litter. He conducts some research and select

podryga [215]

Answer:

c. 6.2 ± 2.626(0.21)

Step-by-step explanation:

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 101 - 1 = 100

99% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 100 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.99}{2} = 0.995$ . So we have T = 2.626

The confidence interval is:

$\overline{x} \pm M$

In which $\overline{x}$ is the sample mean while M is the margin of error.

The distribution of the number of puppies born per litter was skewed left with a mean of 6.2 puppies born per litter.

This means that $\overline{x} = 6.2$

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 2.626\frac{2.1}{\sqrt{101}} = 2.626(0.21)$

In which s is the standard deviation of the sample and n is the size of the sample.

Thus, the confidence interval is:

$\overline{x} \pm M = 6.2 \pm 2.626(0.21)$

And the correct answer is given by option c.

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2 years ago

Samuel deposited money in an account that pays an annual simple interest rate of 3.5%. at the end of 5 years, samuel earns $2625

evablogger [386]

He has deposited 1500 dollars into the account.

4 0

2 years ago

Read 2 more answers

evan has a job selling magazine and newspaper subscriptions. he earns $23 for each magazine subscription and $54 for each newspa

SashulF [63]

First we write the variables already defined:
m = the number of magazine subscriptions sold
n = the number of newspaper subscriptions sold
We now write the system of inequations based on the following facts:
"he earns $ 23 for each magazine subscription and $ 54 for each newspaper subscription that he sells. his goal is to make more than $ 642 per week"
23m + 54n> 642
"I have expectations to sell at least 10 subscriptions per week"
m + n> = 10
Answer:
A system of inequalities that models the given situation is:
23m + 54n> 642
m + n> = 10

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3 years ago

5 + 4x + 6 - 2x<br> explain how you would do it

Alona [7]

Answer:

11+2x

Step-by-step explanation:

5+6=11

4x-2x=2x

8 0

2 years ago

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Patrick is keeping track of how far he jogs each morning.

katrin2010 [14]

Answer:

21:50

Step-by-step explanation:

We need to find the ratio of 420 m to 1 km.

We know that,

1 km = 1000 m

So,

The ratio becomes,

$\dfrac{420\ m}{1\ km}=\dfrac{420\ m}{1000\ m}\\\\=\dfrac{42\ m}{100\ m}\\\\=\dfrac{21}{50}$

So, the required ratio is 21:50.

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2 years ago