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pav-90 [236]
3 years ago
11

If a square has a length of 3x-y, what is its area?

Mathematics
1 answer:
SVEN [57.7K]3 years ago
7 0

Answer:

  9x² -6xy +y²

Step-by-step explanation:

The square of the binomial can be written directly using the relationship ...

  (a +b)² = a² +2ab +b²

where you have a=3x and b=-y.

  area = (3x -y)² = (3x)² + 2(3x)(-y) + (-y)²

  area = 9x² -6xy +y²

You might be interested in
In △ABC, m∠A=16°, m∠B=49°, and a=4. Find c to the nearest tenth.
xenn [34]

Answer:

= 8.33 inches

Step-by-step Explanation

First add 49 + 16, which equals 65, and subtract that result from 180, since a triangle equals 180 degrees and you find out angle C is equal to 115 degrees.

Now using the formula sinA/a = sinB/b = sinC/c, plug in values and you'd get the equation sin49 x 10/sin115. After solving the equation you'd get about  8.32729886047258 inches.

= 8.33

7 0
3 years ago
Read 2 more answers
It took Mrs. Harpole 35 minutes to grade
stepladder [879]

Answer:

700 minutes or 11.67 hours

Step-by-step explanation:

35/4=8.75

8.75*80=700

8 0
3 years ago
A national survey conducted in 2011 among a simple random sample of 1,507 adults shows that 56% of Americans think the Civil War
Drupady [299]

Answer:

a)z=4.658

p_v =P(z>4.65)=1-P(z  

b) Using the significance level assumed \alpha=0.05 we see that p_v so we have enough evidence at this significance level to reject the null hypothesis. And on this case makes sense the claim that the proportion of Americans who thinks that the Civil War is still relevant to American politics and political life is  higher than 50%.

c) The 90% confidence interval would be given (0.527;0.593).

We are confident that about 54% to 59% of all Americans think the Civil War is relevant.

Step-by-step explanation:

I )Part a

1) Data given and notation

n=1507 represent the random sample taken  

X represent the Americans who thinks that the Civil War is still relevant to American politics and political life

\hat p estimated proportion of Americans who thinks that the Civil War is still relevant to American politics and political life in the sample

p_o=0.5 is the value that we want to test since the problem says majority    

\alpha=0.05 represent the significance level (no given, but is assumed)  

z would represent the statistic (variable of interest)  

p_v represent the p value (variable of interest)  

p= population proportion of Americans who thinks that the Civil War is still relevant to American politics and political life

2) Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the proportion of Americans who thinks that the Civil War is still relevant to American politics and political life exceeds 50%(Majority). :  

Null Hypothesis: p \leq 0.5

Alternative Hypothesis: p >0.5

We assume that the proportion follows a normal distribution.  

This is a one tail upper test for the proportion of  union membership.

The One-Sample Proportion Test is "used to assess whether a population proportion \hat p is significantly (different,higher or less) from a hypothesized value p_o".

Check for the assumptions that he sample must satisfy in order to apply the test

a)The random sample needs to be representative: On this case the problem no mention about it but we can assume it.

b) The sample needs to be large enough

np_o =1507*0.5=753.5>10

n(1-p_o)=1507*(1-0.5)=753.5>10

3) Calculate the statistic  

The statistic is calculated with the following formula:

z=\frac{\hat p -p_o}{\sqrt{\frac{p_o(1-p_o)}{n}}}

On this case the value of p_o=0.5 is the value that we are testing and n = 1507.

z=\frac{0.56 -0.5}{\sqrt{\frac{0.5(1-0.5)}{1507}}}=4.658

The p value for the test would be:

p_v =P(z>4.65)=1-P(z  

II) Part b

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

Based on the alternative hypothesis the p value would be given by:

p_v =P(z>4.65)=1-P(z  

Using the significance level assumed \alpha=0.05 we see that p_v so we have enough evidence at this significance level to reject the null hypothesis. And on this case makes sense the claim that the proportion of Americans who thinks that the Civil War is still relevant to American politics and political life is  higher than 50%.

III) Part c

The confidence interval would be given by this formula

\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}

For the 90% confidence interval the value of \alpha=1-0.9=0.1 and \alpha/2=0.05, with that value we can find the quantile required for the interval in the normal standard distribution.

z_{\alpha/2}=2.58

And replacing into the confidence interval formula we got:

0.56 - 2.58 \sqrt{\frac{0.56(1-0.56)}{1507}}=0.527

0.56 + 2.58 \sqrt{\frac{0.56(1-0.56)}{1507}}=0.593

And the 90% confidence interval would be given (0.527;0.593).

We are confident that about 54% to 59% of all Americans think the Civil War is relevant.

And this result agrees with the result of part b, since the interval not contains the value of 0.5 we can conclude that the proportion of Americans who thinks that the Civil War is still relevant to American politics and political life it's higher than 0.5 at 90% of confidence.

7 0
2 years ago
WILL MARK AS BRAINLIEST PLEASE HELP!!!
neonofarm [45]

Step-by-step explanation:

2x = y-10

Rewrite as: 2x + 10 = y

Therefore:

2x+10 = y

2x +7 = 2y

Subtract the equations:

 2x + 10 = y

- 2x + 7 = 2y

______________

          3 = -y

Therefore y = -3

Substiture y = -3 into the second equation:

2x + 7 = 2(-3)

2x + 7 = -6

2x = -13

x= -6.5

Answer : (-6.5, -3)

3 0
3 years ago
Read 2 more answers
What is the product? One-eighth times three-elevenths 3 over 88 1 over 22 4 over 19 35 over 88
kipiarov [429]

Answer:

\frac{3}{88}

Step-by-step explanation:

Given

One-eighth times three-elevenths

Required

Solve

One-eighth means 1/8

Three-elevenths means 3/11

So, mathematically; the above expression is represented as thus:

\frac{1}{8} * \frac{3}{11}

To solve this, we simply multiply the numerator and the denominator together.

After multiplying these together, the next is to check if the resulting can be simplified

If yes,we simplify it and if otherwise, we live it like that.

So,

\frac{1}{8} * \frac{3}{11}

=\frac{1 * 3}{8 * 11}

= \frac{3}{88}

At this point, the fraction can't be simplified any further.

Hence,

\frac{1}{8} * \frac{3}{11} = \frac{3}{88}

3 0
2 years ago
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