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3 years ago

Help please! Will award brainliest!

Mathematics

1 answer:

emmasim [6.3K]3 years ago

5 0

C. (2x - 5)

<u>Explanation:</u>

Given:

The factors of $4x^2 - 25$ = ?

The binomial factor can be simplified and written as

$4x^2 - 25 = (2x + 5) (2x - 5)$

When these two factors are multiplied then they give 4x² - 25

Thus, (2x + 5) and (2x - 5) are the two factors of 4x² - 25

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If books cost $3.50 each, how much will 3 books cost in all?

Tamiku [17]

Answer:

3.50*3=10.5

the total will be $10.50

Step-by-step explanation:

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3 years ago

The area of a circle is 81 ft 2 . What is the π circumference? Leave in terms of Pi.

KonstantinChe [14]

Answer:

10.2π

Step-by-step explanation:

Given data

Area of circle= 81 ft^2

Also, the expression for the area of a circle is

A=πr^2

substitute

81=3.142*r^2

r^2= 81/3.142

r^2= 25.77

square both sides

r= √25.77

r= 5.1

Also, the expression for the circumference is

C= 2πr

substitute

C= 2*π*5.1

C= 10.2π

Hence the circumference is 10.2π

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3 years ago

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zhannawk [14.2K]

Answer:
I’m sorry but I can’t answer until you explain

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3 years ago

You recently sent out a survey to determine if the percentage of adults who use social media has changed from 66%, which was the

il63 [147K]

Answer:

The 98% confidence interval estimate of the proportion of adults who use social media is (0.56, 0.6034).

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 $1 - \frac{\alpha}{2}$ .

Of the 2809 people who responded to survey, 1634 stated that they currently use social media.

This means that $n = 2809, \pi = \frac{1634}{2809} = 0.5817$

98% confidence level

So $\alpha = 0.02$ , z is the value of Z that has a pvalue of $1 - \frac{0.02}{2} = 0.99$ , so $Z = 2.327$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.5817 - 2.327\sqrt{\frac{0.5817*4183}{2809}} = 0.56$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.5817 + 2.327\sqrt{\frac{0.5817*4183}{2809}} = 0.6034$

The 98% confidence interval estimate of the proportion of adults who use social media is (0.56, 0.6034).

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2 years ago

A dance academy charges $24 per class and a one-time registration fee of $15. a student paid a total of $687 to the academy. fin

Georgia [21]

28 is the correct answer

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3 years ago