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3 years ago

X - y = 3 x + 3y = 9

2 answers:

7 0

Solve for one of the variables in the first equation (in this case, I will solve for X):
X = Y + 3

Then use that value of X in the second equation to solve for Y:
X + 3Y = 9
(Y + 3) + 3Y = 9
4Y + 3 = 9
4Y = 6
Y = 1.5

Use the value of Y we just found in the X equation we created:
X = Y + 3
X = 1.5 + 3
X = 4.5

Therefore X = 4.5 or 9/2 and Y = 1.5 or 3/2.

Verizon [17]3 years ago

3 0

X - y = 3 is the same as x=3+y 

3+y+3y = 9 

3+4y=9 

4y=9-3

4y=6

y=6/4

y=3/2 

x-(3/2)=3 

x=3+(3/2) 

x=6/2+3/2 


x=9/2

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A dolphin can swim up to 40 miles per hour.what is the speed in feet per hour?

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3 years ago

According to the 2010 census, the state of Oregon has a population of 40 people per square mile. If a county in Oregon measured

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90000

Step-by-step explanation:

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3 years ago

In a recent year, Washington State public school students taking a mathematics assessment test had a mean score of 276.1 and a s

Oksi-84 [34.3K]

Answer:

a) $\mu_{\bar x} =\mu = 276.1$

$\sigma_{\bar x} =\frac{\sigma}{\sqrt{n}}=\frac{34.4}{\sqrt{64}}=4.3$

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

$\bar X \sim N(\mu=276.1, \frac{\sigma}{\sqrt{n}}=4.3)$

c) $P(\bar X \geq 285)=P(Z\geq \frac{285-276.1}{4.3}=2.070)$

$P(Z\geq2.070)=1-P(Z$

Step-by-step explanation:

Let X the random variable the represent the scores for the test analyzed. We know that:

$\mu=E(X) = 276.1 , \sigma=Sd(X) = 34.4$

And we select a sample size of 64.

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".

Part a

For this case the mean and standard error for the sample mean would be given by:

$\mu_{\bar x} =\mu = 276.1$

$\sigma_{\bar x} =\frac{\sigma}{\sqrt{n}}=\frac{34.4}{\sqrt{64}}=4.3$

Part b

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

$\bar X \sim N(\mu=276.1, \frac{\sigma}{\sqrt{n}}=4.3)$

Part c

For this case we want this probability:

$P(\bar X \geq 285)$

And we can use the z score defined as:

$z=\frac{\bar x -\mu}{\sigma_{\bar x}}$

And using this we got:

$P(\bar X \geq 285)=P(Z\geq \frac{285-276.1}{4.3}=2.070)$

And using a calculator, excel or the normal standard table we have that:

$P(Z\geq2.070)=1-P(Z$

8 0

3 years ago

Please help I’m stuck!!!

Anika [276]

Answer:

The value of angle B is 33.69°

Step-by-step explanation:

You can find out using Tangent Rule, tanθ = oppo./adj. where opposite and adjacent are the length of triangle :

oppo. = AC = 6 units

adj. = BC = 9 units

θ = ∠B

tan ∠B = AC/BC

tan ∠B = 6/9

∠B = tan^(-1) (6/9)

= 33.69° (near. hundredth)

3 0

3 years ago