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3 years ago

X-5y-z=-20-2x-y-6z=25-x-4y-z=-15Solve by elimination

Mathematics

1 answer:

Tju [1.3M]3 years ago

6 0

Answer:

x = 0

y = 5

z = -5.

Step-by-step explanation:

X-5y-z=-20

-2x-y-6z=25

-x-4y-z=-15

Add equation 1 and 3:

-9y - 2z = -35 .......... A

Multiply the first equation by 2:

2x - 10y - 2z = -40

Now add this to equation 2:

-11y -8z = -15.............B

Now multiply equation A by -4:

36y + 8x = 140.........C

Add equations B and C:

25y = 125

y = 5.

Substitute for y in equation A:

-9*5 - 2z = -35

2z = -45 + 35 = - 10

z = -5.

Now find x by substituting for y and z in the first equation:

x - 5(5) - (-5) = -20

x - 20 = -20

x = 0.

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slamgirl [31]

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3 years ago

Un edificio proyecta una sombra de 7.5m.mientras que un arbol que mide 1.6 m de altura proyecta una sombra 1.85 M¿Cual es la alt

sattari [20]

Answer: The height of the building is 6.49 meters.

Step-by-step explanation:

This can be translated to:

"A building projects a 7.5 m shadow, while a tree with a height of 1.6 m projects a shadow of 1.85 m.

Which is the height of the building?"

We can conclude that the ratio between the projected shadow is and the actual height is constant for both objects, this means that if H is the height of the building, we need to have:

(height of the building)/(shadow of the building) = (height of the tree)/(shadow of the tree)

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2 years ago

Determine which measure of center best represents the best data. Explain.

Monica [59]

Answer:

Step-by-step explanation:

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I would choose the median, because the mode is the same answer and that's a good enough reason for choosing anything. 2 out 3 isn't bad as they say in Baseball.

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3 years ago

A study was designed to investigate the effects of two variables, (1) A student's level of mathematical anxiety and (2) teach

Mashcka [7]

Answer:

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And we can find this probability using the complement rule:

$P(z>-2)=1-P(z$

And in order to find these probabilities we can find tables for the normal standard distribution, excel or a calculator.

$P(z>-2)=1-P(z$

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 scores of a population, and for this case we know the distribution for X is given by:

$X \sim N(440,20)$