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4 years ago

Which properties of equality justify steps b and d?

Mathematics

2 answers:

QveST [7]4 years ago

8 0

C) Subtraction Property of Equality; Multiplication Property of Equality

- Prodixy ☕

7nadin3 [17]4 years ago

4 0

C. Subtraction Property of Equality; Multiplication Property of Equality

For the first one, you are subtracting 7 from both sides (step b), to help isolate the y

since you are both subtracting, and "both sides" (meaning there is a equal sign) it is Subtraction Property of Equality.

For the second one, you are multiplying 2 from both sides (step d), to help isolate the y

since you are multiplying, and "both sides" (meaning there is a equal sign), it is Multiplication Property of Equality

hope this helps

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A number x increased by 8 is greater than 26

Julli [10]

Answer:

x+8<26

Hope this helped!

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3 years ago

Choose the symbol that correctly compares the fractions below. 8/9 ? 1/9

gladu [14]

Answer:

Which means that this equation is also true: 8/9 > 1/9

Step-by-step explanation:

Is 8/9 less than 1/9? Is 8/9 smaller than 1/9? These are the same questions with one answer.

To get the answer, we first convert each fraction into decimal numbers. We do this by dividing the numerator by the denominator for each fraction as illustrated below:

8/9 = 0.889

1/9 = 0.111

Then, we compare the two decimal numbers to get the answer.

0.889 is not less than 0.111.

Therefore, 8/9 is not less than 1/9 and the answer to the question "Is 8/9 less than 1/9?" is no.

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3 years ago

What is the correct order of operations for simplifying the expression 2 - 3x + 5 + 71 - 5x)2+x

lisov135 [29]

Answer:

Your answer would be: square the binomial, distribute 7 inside the parentheses, and then combine like terms

Step-by-step explanation:

6 0

2 years ago

Grading managers. Some companies "grade on a bell curve" to compare the performance of their managers and professional workers.

Monica [59]

Answer:

$\mu = 250, \sigma = 175.781$

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".

Solution to the problem

Let X the random variable that represent the grades of a population, and for this case we know the distribution for X is given by:

$X \sim N(\mu,\sigma)$

For this case we have two conditions given:

$P(X$

$P(X>475) = 0.1$ or equivalently $P(X$

And the best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\sigma}$

So we can find a value from the normal standard distribution that accumulates 0.1 and 0.9 of the area in the left, for this case the two values are:

$z= -1.28, z=-1.28$

We can verify that P(Z<-1.28) =0.1[/tex] and P(Z<1.28) =0.9[/tex]

And then using the z score we have the following formulas:

$-1.28 = \frac{25 -\mu}{\sigma}$ (1)

$1.28 = \frac{475 -\mu}{\sigma}$ (2)

If we add equations (1) and (2) we got:

$\frac{25 -\mu}{\sigma} + \frac{475 -\mu}{\sigma} =0$

We can multiply both sides of the equation by $\sigma$ and we got:

$25+ 475 -2 \mu = 0$

$\mu = \frac{500}{2}= 250$

And then we can find the standard deviation for example from equation (1) and we got:

$\sigma = \frac{25-250}{-1.28}=175.781$

So then the answer would be:

$\mu = 250, \sigma = 175.781$

3 0

3 years ago

In melanie's styling salon, the time to complete a simple haircut is normally distributed with a mean of 25 minutes and a standa

vovikov84 [41]

They will require between 18.42 and 31.58 minutes.

We want the middle 90%. The two probability values associated with this would be 0.95 and 0.05; this would leave 5% below and 5% above, giving us the middle 90%.

Using a z-table (http://www.z-table.com) we see that the z-score associated with an area to the left of 0.05 is between -1.64 and -1.65; since it is equally distant from both we will use -1.645.

The z-score associated with an area of the left of 0.95 is between 1.64 and 1.65; since it is equally distant from both we will use 1.645.

The formula for a z-score is

z = (X-μ)/σ
-1.645 = (X-25)/4

Multiplying by 4 on both sides,
-1.645(4) = X-25
-6.58 = X-25

Adding 25 to both sides,
-6.58+25 = X
18.42 = X

For the upper bound,
1.645 = (X-25)/4

Multiplying both sides by 4,
1.645(4) = X-25
6.58 = X-25

Adding 25 to both sides,
6.58+25 = X
31.58 = X

The times are between 18.42 and 31.58 minutes.

6 0

3 years ago