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3 years ago

Help please

Mathematics

2 answers:

tester [92]3 years ago

6 0

Answer:

64y² - 81

Step-by-step explanation:

(8y +9)(8y - 9)

64y² - 72y + 72y - 81

64y² - 81

tatuchka [14]3 years ago

6 0

<u>Answer:</u>

<h3>. 64y² - 81</h3><h3>. the product is a difference of squares</h3>

<u>Explanation:</u>

(8y + 9)(8y - 9) = 64y² - 81

the product is a difference of squares

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How do you solve for x in this equation. 4^x-3=18

Lostsunrise [7]

Answer:

x = ln(21)/ ln(4), Decimal Form: 2.19615871

Step-by-step explanation:

This is pretty complex math for middle school with logarithms and what not. Make sure you typed the problem in correctly. If you did, I guess that's your answer.

3 0

3 years ago

Let x denote the lifetime of a mcchine component with an exponential distribution. The mean time for the component failure is 25

aliina [53]

Answer:

0.1353 = 13.53% probability that the lifetime exceeds the mean time by more than 1 standard deviations

Step-by-step explanation:

Exponential distribution:

The exponential probability distribution, with mean m, is described by the following equation:

$f(x) = \mu e^{-\mu x}$

In which $\mu = \frac{1}{m}$ is the decay parameter.

The probability that x is lower or equal to a is given by:

$P(X \leq x) = \int\limits^a_0 {f(x)} \, dx$

Which has the following solution:

$P(X \leq x) = 1 - e^{-\mu x}$

The probability of finding a value higher than x is:

$P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^{-\mu x}) = e^{-\mu x}$

The mean time for the component failure is 2500 hours.

This means that $m = \frac{2500}, \mu = \frac{1}{2500} = 0.0004$

What is the probability that the lifetime exceeds the mean time by more than 1 standard deviations?

The standard deviation of the exponential distribution is the same as the mean, so this is P(X > 5000).

$P(X > x) = e^{-0.0004*5000} = 0.1353$

0.1353 = 13.53% probability that the lifetime exceeds the mean time by more than 1 standard deviations

4 0

3 years ago

A taxi driver had 27 fares to and from the airport last Monday. The price for a ride to the airport is $14, and the price for a

OLga [1]

Answer:

(15, 12)

Step-by-step explanation:

Let's generate two systems of equations that fit this scenario.

Number of trips to the airport = x

Number of trips from the airport = y

Total number of trips to and from the airport = 27

Thus:

$x + y = 27$ => equation 1.

Total price for trips to the Airport = 14*x = 14x

Total price of trips from the airport = 7*y = 7y

Total collected for the day = $294

Thus:

$14x + 7y = 294$ => equation 2.

Multiply equation 1 by 7, and multiply equation 2 by 1 to make both equations equivalent.

7 × $x + y = 27$

1 × $14x + 7y = 294$

Thus:

$7x + 7y = 189$ => equation 3

$14x + 7y = 294$ => equation 4

Subtract equation 4 from equation 3

-7x = -105

Divide both sides by -7

x = 15

Substitute x = 15 in equation 1

$x + y = 27$

$15 + y = 27$

Subtract both sides by 15

$y = 27 - 15$

$y = 12$

The ordered pair would be (15, 12)

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3 years ago

In a normal distribution, a data value located 0.8 standard deviations below the mean has Standard Score: z =

Svetlanka [38]

Answer:

z= a letter before y

Step-by-step explanation:

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3 years ago

Bag contains 2 red marbles 2Green marbles and 4 blue marbles if we choose a marble than other marble without putting the first o

Murrr4er [49]

Answer:

The probability that the first marvel will be red and the second will be green is 7.14%.

Step-by-step explanation:

Since a bag contains 2 red marbles, 2 green marbles and 4 blue marbles, if we choose a marble and then other marble without putting the first one back in the bag, to determine what is the probability that the first marvel will be red and the second will be green, the following calculation must be performed:

2 + 2 + 4 = 8

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0.25 x 0.2857 = X

0.0714 = X

Therefore, the probability that the first marvel will be red and the second will be green is 7.14%.

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2 years ago