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2 years ago

What description represents the expression 5x -9?

Mathematics

1 answer:

mixer [17]2 years ago

6 0

Answer:

A: 9 is subtracted from the product of 5 and a number.

Step-by-step explanation:

We know this because when a varible is place directly next to a number then the number is being multiplied by an unknow number. So in this equation five is being multiplied by an unknown number and nine is being subtracted from that.

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According to a survey, 65% of murders committed last year were cleared by arrest or exceptional means. Fifty murders committed

monitta

Answer:

a) $P(X=41)=(50C41)(0.65)^{41} (1-0.65)^{50-41}=0.00421$

b) $P(X=36)=(50C36)(0.65)^{36} (1-0.65)^{50-36}=0.0714$

$P(X=37)=(50C37)(0.65)^{37} (1-0.65)^{50-37}=0.0502$

$P(X=38)=(50C38)(0.65)^{38} (1-0.65)^{50-38}=0.0319$

And adding these values we got:

$P(36 \leq X \leq 38)= 0.1535$

c) We can find the expected value given by:

$E(X) = np =50*0.65 = 32.5$

And the standard deviation would be:

$\sigma = \sqrt{np(1-p)} \sqrt{50*0.65*(1-0.65)}= 3.373$

We can use the approximation to the normal distribution and we have at leat 95% of the data within 2 deviations from the mean. And the lower limit for this case would be:

$\mu -2\sigma = 32.5- 2*3.373 = 25.75$

And then we can consider a value of 18 as unusual lower for this case.

Step-by-step explanation:

Let X the random variable of interest "number cleared by arrest or exceptional", on this case we can model this variable with this distribution:

$X \sim Binom(n=50, p=0.65)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

We want this probability:

$P(X=41)=(50C41)(0.65)^{41} (1-0.65)^{50-41}=0.00421$

Part b

We want this probability:

$P(36 \leq X \leq 38)$

We can find the individual probabilities:

$P(X=36)=(50C36)(0.65)^{36} (1-0.65)^{50-36}=0.0714$

$P(X=37)=(50C37)(0.65)^{37} (1-0.65)^{50-37}=0.0502$

$P(X=38)=(50C38)(0.65)^{38} (1-0.65)^{50-38}=0.0319$

And adding these values we got:

$P(36 \leq X \leq 38)= 0.1535$

Part c

We can find the expected value given by:

$E(X) = np =50*0.65 = 32.5$

And the standard deviation would be:

$\sigma = \sqrt{np(1-p)} \sqrt{50*0.65*(1-0.65)}= 3.373$

We can use the approximation to the normal distribution and we have at leat 95% of the data within 2 deviations from the mean. And the lower limit for this case would be:

$\mu -2\sigma = 32.5- 2*3.373 = 25.75$

And then we can consider a value of 18 as unusual lower for this case.

6 0

3 years ago

On a map 180 miles are represented by 4 inches. how many miles are represented by 6 inches

Dmitry [639]

180/4 = x/6
4x=1080
x=270 miles

4 0

3 years ago

Describe the nature of the roots for this equation.<br> 3x^2+x-5= 0

m_a_m_a [10]

Answer:

<h2>This equation has no natural roots.</h2>

Step-by-step explanation:

$3x^2+x-5=0\\\\\text{Use the quadratic formula for}\ ax^2+bx+c=0\\\\x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}\\\\\text{For the given equation:}\\\\a=3,\ b=1,\ c=-5\\\\b^2-4ac=1^2-4(3)(-5)=1+60=61\\\\x=\dfrac{-1\pm\sqrt{61}}{(2)(3)}=\dfrac{-1\pm\sqrt{61}}{6}\notin\mathbb{N}$

4 0

2 years ago

Read 2 more answers

Select all the correct answers. If the measure of angle 0 is 5(pi)/4, which statements are true?

elixir [45]

Finding the equivalent angle of $\theta$ , the correct statements are given as follows:

The Measure of the reference angle is 45.

$\cos{\theta} = \frac{\sqrt{2}{2}}$ .

$\tan{\theta} = 1$

$\sin{\theta} = \frac{\sqrt{2}{2}}$ .

<h3>What are equivalent angles?</h3>

Each angle on the second, third and fourth quadrants will have an equivalent on the first quadrant.

In this problem, the given angle is as follows:

$\theta = \frac{5\pi}{4}$

It is on the third quadrant, as it is between pi and 1.5 pi, hence the equivalent on the first quadrant, also known as the reference angle, is given by:

$\frac{5\pi}{4} - \pi = \frac{5\pi}{4} - \frac{4\pi}{4} = \frac{\pi}{4}$

The angle of 45º has equal sine and cosine, and tangent of 1, hence the correct statements are:

The Measure of the reference angle is 45.

$\cos{\theta} = \frac{\sqrt{2}{2}}$ .

$\tan{\theta} = 1$

$\sin{\theta} = \frac{\sqrt{2}{2}}$ .

More can be learned about equivalent angles at brainly.com/question/24787111

#SPJ1

8 0

1 year ago

A price is decreased by 24% and is now £372.40.<br>Work out the original price.

goldfiish [28.3K]

Answer:

Step-by-step explanation:

Subtract the discount from 100 to get the percentage of the original price.

Multiply the final price by 100.

Divide by the percentage in Step One

5 0

2 years ago