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crimeas [40]
2 years ago
8

{4x+y=9 and 5x +2y=9

Mathematics
1 answer:
GaryK [48]2 years ago
5 0

Answer:

x=3,y=-3

Step-by-step explanation:

Isolate x for 4x +y=9: x=9-y/4

Substitute x = 9-y/4

[5 x 9-y/4+2y =9]

Isolate y for (45+3y/4)=9:

y=-3

For x= 9-y/4

Substitute y = -3

x= 9-(-3)/4

9-(-3)/4=3

X=3

The solutions to the system of equations are:

x=3 y= -3

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Find the quotient. Write your answer in simplest form.<br><br> 1/3 ÷ 6= 1/18?
Anna007 [38]
If you would like to solve 1/3 / 6, you can do this using the following steps:

1/3 / 6 = 1/3 / 6/1 = 1/3 * 1/6 = 1/18

The correct result would be 1/18.
8 0
2 years ago
The mean annual income for people in a certain city is 37 thousand dollars, with a standard deviation of 28 thousand dollars. A
Aloiza [94]

Answer:

P( 31 < \bar X< 41)

And we can ue the z score formula given by:

z= \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}

And using this formula we got for the limits:

z = \frac{31-37}{\frac{28}{\sqrt{50}}}= -1.515

z = \frac{41-37}{\frac{28}{\sqrt{50}}}= 1.01

So we want to find this probability:

P(-1.515

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 annual income of a population, and for this case we know the following info:

\mu=37 and \sigma=28  and we are omitting the zeros from the thousand to simplify calculations

We select a sample size of n=50>30.

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

From the central limit theorem we know that the distribution for the sample mean \bar X is given by:

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

And we want to find this probability:

P( 31 < \bar X< 41)

And we can ue the z score formula given by:

z= \frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}

And using this formula we got for the limits:

z = \frac{31-37}{\frac{28}{\sqrt{50}}}= -1.515

z = \frac{41-37}{\frac{28}{\sqrt{50}}}= 1.01

So we want to find this probability:

P(-1.515

4 0
3 years ago
What are two other ways to name plane V?
astraxan [27]
Two other ways to name plane V are

plane ANCRMX

plane XMRCNA
5 0
2 years ago
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you are invited to a family dinner, you decide to make cupcakes for desert for everyone including yourself. while calculating th
Amiraneli [1.4K]
Based on the given description above, and the number of guests that is expected to arrive in the family dinner, The minimum number of cupcakes that you will need to bring so that everybody could get at least one cupcake is 23. You should have at least 23 cupcakes. Hope this is the answer that you are looking for. Thanks for posting!
3 0
3 years ago
Given the polynomial 2x^3+18x^2-18x-162, what is the value of the constant "k" in the factored form?
maxonik [38]
2x³+18x²<span>-18x-162 = 
2(</span>x³+9x²-9x-81)=
2(x²(x+9)-9(x+9))=
2(x²-9)(x+9)=
2(x+3)(x-3)(x+9)

Answer: k=3
7 0
2 years ago
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