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3 years ago

9y - 3 (if y = 10)..

Mathematics

2 answers:

Aloiza [94]3 years ago

7 0

9(10)-3
90-3
87 would be your answer

podryga [215]3 years ago

5 0

Step-by-step explanation:

9y-3=?

9(10)-3

=90-3

=87

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13 of 15

Slav-nsk [51]

Answer:

(√30 - 1, 0)
(-√30 - 1, 0)

Step-by-step explanation:

Making the equation of the parabola :

⇒ y = a(x - h)² + k

⇒ y = (x + 1)² - 17 - 13

⇒ y = (x + 1)² - 30

x-intercepts have y = 0 :

0 = (x + 1)² - 30
(x + 1)² = 30

Taking the square root on each side :

√(x + 1)² = √30
x + 1 = ±√30
x = ±√30 - 1

The x-intercepts are :

(√30 - 1, 0)
(-√30 - 1, 0)

7 0

2 years ago

The length of a rectangle is 6m longer than its width. If the perimeter of the rectangle is 52m, find its area

sveticcg [70]

If length is x, then width is 6+x
Perimeter = 2*(x + 6+x) = 52 
2*6 + 2*2x = 52 
4x = 52 - 12 = 40 
x = 40/4 = 10 

Area = length*width = 10*(6+10) 
Area = 10*16 = 160 meter square

4 0

3 years ago

F(x)=8_-4x-x^3. g(x)=x^2+7x-9. Find f(x)+g(x)

11111nata11111 [884]

$(8 - 4x - {x}^{3} ) + ( {x}^{2} + 7x - 9) \\ = - {x}^{3} + {x}^{2} - 4x + 7x + 8 - 9 \\ = - {x}^{3} + {x}^{2} + 3x - 1$
$(8x - 4x - {x}^{3} ) + ( {x}^{2} + 7x - 9) \\ - {x}^{3} + {x}^{2} + 8x - 4x + 7x - 9 \\ - {x}^{3} + {x}^{2} + 11x - 9$
The answer is either B, and you forgot to put in the ^2 in the answer choice, or C, and you forgot to put an x where there is a _ in the question.

Check the actual question (the one you recieved, not the one posted here) and see where the mistakes are. If f(x) = 8x - 4x - x^3, then your answer is C. However, if B is actually -x^3 + x^2 + 3x - 1, then the answer is B.

7 0

4 years ago

The CPA Practice Advisor reports that the mean preparation fee for 2017 federal income tax returns was $273. Use this price as t

skad [1K]

Answer:

a) 0.6212 = 62.12% probability that the mean price for a sample of 30 federal income tax returns is within $16 of the population mean.

b) 0.7416 = 74.16% probability that the mean price for a sample of 50 federal income tax returns is within $16 of the population mean.

c) 0.8804 = 88.04% probability that the mean price for a sample of 100 federal income tax returns is within $16 of the population mean.

d) None of them ensure, that one which comes closer is a sample size of 100 in option c), to guarantee, we need to keep increasing the sample size.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

The CPA Practice Advisor reports that the mean preparation fee for 2017 federal income tax returns was $273. Use this price as the population mean and assume the population standard deviation of preparation fees is $100.

This means that $\mu = 273, \sigma = 100$

A) What is the probability that the mean price for a sample of 30 federal income tax returns is within $16 of the population mean?

Sample of 30 means that $n = 30, s = \frac{100}{\sqrt{30}}$

The probability is the p-value of Z when X = 273 + 16 = 289 subtracted by the p-value of Z when X = 273 - 16 = 257. So

X = 289

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{289 - 273}{\frac{100}{\sqrt{30}}}$

$Z = 0.88$

$Z = 0.88$ has a p-value of 0.8106

X = 257

$Z = \frac{X - \mu}{s}$

$Z = \frac{257 - 273}{\frac{100}{\sqrt{30}}}$

$Z = -0.88$

$Z = -0.88$ has a p-value of 0.1894

0.8106 - 0.1894 = 0.6212

0.6212 = 62.12% probability that the mean price for a sample of 30 federal income tax returns is within $16 of the population mean.

B) What is the probability that the mean price for a sample of 50 federal income tax returns is within $16 of the population mean?

Sample of 30 means that $n = 50, s = \frac{100}{\sqrt{50}}$

X = 289

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{289 - 273}{\frac{100}{\sqrt{50}}}$

$Z = 1.13$

$Z = 1.13$ has a p-value of 0.8708

X = 257

$Z = \frac{X - \mu}{s}$

$Z = \frac{257 - 273}{\frac{100}{\sqrt{50}}}$

$Z = -1.13$

$Z = -1.13$ has a p-value of 0.1292

0.8708 - 0.1292 = 0.7416

0.7416 = 74.16% probability that the mean price for a sample of 50 federal income tax returns is within $16 of the population mean.

C) What is the probability that the mean price for a sample of 100 federal income tax returns is within $16 of the population mean?

Sample of 30 means that $n = 100, s = \frac{100}{\sqrt{100}}$

X = 289

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$Z = \frac{289 - 273}{\frac{100}{\sqrt{100}}}$

$Z = 1.6$

$Z = 1.6$ has a p-value of 0.9452

X = 257

$Z = \frac{X - \mu}{s}$

$Z = \frac{257 - 273}{\frac{100}{\sqrt{100}}}$

$Z = -1.6$

$Z = -1.6$ has a p-value of 0.0648

0.9452 - 0.0648 =

0.8804 = 88.04% probability that the mean price for a sample of 100 federal income tax returns is within $16 of the population mean.

D) Which, if any of the sample sizes in part (a), (b), and (c) would you recommend to ensure at least a .95 probability that the same mean is withing $16 of the population mean?

None of them ensure, that one which comes closer is a sample size of 100 in option c), to guarantee, we need to keep increasing the sample size.

6 0

3 years ago

How many centimeters are in 2.5 meters?

devlian [24]

Answer:

250

Step-by-step explanation:

1 meter = 100 centimeters

2.5 x 100 = 250

7 0

3 years ago

Read 2 more answers