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3 years ago

2. Which values of x and y make the system of linear equations true?

Mathematics

2 answers:

adelina 88 [10]3 years ago

6 0

Answer:

see below

Step-by-step explanation:

attached

Stels [109]3 years ago

5 0

Answer:

X=-4 Y= 5

Step-by-step explanation:

solving the equation simultaneously

4X+7Y = 19-------------(1)

Y- X = 9-------------(2)

from equation (2),

Y = 9+X ----------------(3)

substituting equation (3) into equation (2)

4X+7(9+X)=19

removing bracket

4X+63+7X= 19

11x = 19-63

11X = -44

X= -44/11

X= -4

put X equal- 4 into equation (3)

Y= 9+-4

Y= 5

therefore, X= -4 Y = 5

therefore,

<h2>for the system of linear equation to be true, x must be= -4 and Y = 5</h2>

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-x + 4y = 6 what is the slope of the line in equation above <br><br> Quick pleaseee

Marina86 [1]

Answer:

-1

Step-by-step explanation:

y=mx+c / the number in front of X is the slop or the gradient number

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3 years ago

A sample of size 6 will be drawn from a normal population with mean 61 and standard deviation 14. Use the TI-84 Plus calculator.

AVprozaik [17]

Answer:

$X \sim N(61,14)$

Where $\mu=61$ and $\sigma=14$

Since the distribution for X is normal then the distribution for the sample mean is also normal and given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

$\mu_{\bar X} = 61$

$\sigma_{\bar X}= \frac{14}{\sqrt{6}}= 5.715$

So then is appropiate use the normal distribution to find the probabilities for $\bar X$

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". The letter $\phi(b)$ is used to denote the cumulative area for a b quantile on the normal standard distribution, or in other words: $\phi(b)=P(z$

Solution to the problem

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

$X \sim N(61,14)$

Where $\mu=61$ and $\sigma=14$

Since the distribution for X is normal then the distribution for the sample mean $\bar X$ is also normal and given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

$\mu_{\bar X} = 61$

$\sigma_{\bar X}= \frac{14}{\sqrt{6}}= 5.715$

So then is appropiate use the normal distribution to find the probabilities for $\bar X$

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3 years ago

Combine like terms to create an equivalent expression. Enter any coefficients as simplified proper or improper fractions or inte

Sonja [21]

Answer:

1 -9/7n

Step-by-step explanation:

$\dfrac{1}{7}-3\left(\dfrac{3}{7}n-\dfrac{2}{7}\right)=\dfrac{1}{7}-\dfrac{3\cdot3}{7}n+\dfrac{3\cdot2}{7}=\dfrac{1}{7}+\dfrac{6}{7}-\dfrac{9}{7}n\\\\=\dfrac{1+6}{7}-\dfrac{9}{7}n=\boxed{1-\dfrac{9}{7}n}$