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Vedmedyk [2.9K]

2 years ago

9

Clara found the product of 3 – 6y2 and y2 + 2. Her work is shown below.

2 answers:

Kisachek [45]2 years ago

6 0

Answer: No the students work is not correct. Because you are using distribution. Which means that 3 has to multiply the y2 and 2 not just the y2! And after you distribute it you need to simplify!

Step-by-step explanation:

nika2105 [10]2 years ago

4 0

Answer:

(3 – 6y²)(y² + 2) = - 6y⁴ - 9y² + 6

Step-by-step explanation:

Given the expression

3-6y² and y²+2

We have to find the product of 3-6y² and y²+2

Clara's Solution:

(3 – 6y²)(y² + 2) = 3(y²) + (–6y²)(2)

= 3y² – 12y²

= -9y²

NO!

The student's work is INCORRECT!

Clara did not imply the correct distribution of multiplying the terms in the first step.

Here is the correct solution:

(3 – 6y²)(y² + 2) = 3(y²) + (–6y²)(2) + (3)(2) + (–6y²)(y²)

= 3y² – 12y² + 6 - 6y⁴

= - 6y⁴ - 9y² + 6

Therefore,

(3 – 6y²)(y² + 2) = - 6y⁴ - 9y² + 6

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Answer:

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A boat traveled 128 kilometers in

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Answer:

The Distance cover by boat in 2 hours and 15 minutes is 72 km

Step-by-step explanation:

Given as :

The Distance cover by boat = 128 kilometer

The time taken is 4 hours

As , Distance = Speed ×Time

So , Speed = $\frac{Diastance}{Time}$

Or, Speed = $\frac{128 km}{4 hours}$

∴ Speed = 32 km per hour

Now, again The boat travel 2 hours and 15 minutes further with speed 32 kmph

So, Time2 = 2 + $\frac{15}{60}$

Or, Time2 = 2 + $\frac{1}{4}$

I.e Time2 = $\frac{9}{4}$ hours

Again , Distance = Speed ×Time

So , Distance = 32kmph × $\frac{9}{4}$ hours

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2 years ago

The floor of a storage unit is 5 feet

Oliga [24]

I don’t know but I hope you had a good day

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2 years ago

The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and

Firdavs [7]

Answer:

1a

$P(39 < X < 48 ) = 0.8767$

1b

95% of all sample means will fall between $40.1 < \mu < 49.9$

1c

$\= x = 41. 795$

2

$n = 25$

Step-by-step explanation:

From the question we are told that

The mean is $n = 45$

The population standard deviation is $\sigma = 10$

The sample size is n = 16

Generally the standard error of the mean is mathematically represented as

$\sigma_{x} = \frac{ \sigma}{\sqrt{n} }$

=> $\sigma_{x} = \frac{ 10 }{\sqrt{16 } }$

=> $\sigma_{x} = 2.5$

Generally the probability that the sample mean will be between 39 and 48 minutes is

$P(39 < X < 48 ) = P( \frac{ 39 - 45}{ 2.5} < \frac{X - \mu }{\sigma } < \frac{ 48 - 45}{ 2.5} )$

=> $P(39 < X < 48 ) = P(-2.4 < Z< 1.2 )$

=> $P(39 < X < 48 ) = P( Z< 1.2 ) - P(Z < -2.4)$

From the z table the area under the normal curve to the left corresponding to 1.2 and -2.4 is

=> $P( Z< 1.2 ) = 0.88493$

and

$P( Z< - 2.4 ) = 0.0081975$

So

$P(39 < X < 48 ) = 0.88493 -0.0081975$

=> $P(39 < X < 48 ) = 0.8767$

From the question we are told the confidence level is 95% , hence the level of significance is

$\alpha = (100 - 95 ) \%$

=> $\alpha = 0.05$

Generally from the normal distribution table the critical value of is

$Z_{\frac{\alpha }{2} } = 1.96$

Generally the margin of error is mathematically represented as

$E = Z_{\frac{\alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E = 1.96 * 2.5$

=> $E =4.9$

Generally the 95% of all sample means will fall between

$\mu -E < and \mu +E$

=> $45 -4.9\ and \ 45 + 4.9$

Generally the value which 90% of sample means is greater than is mathematically represented

$P( \= X > \= x ) = 0.90$

=> $P( \= X > \= x ) = P( \frac{\= X - \mu }{ \sigma_x} > \frac{\= x -45 }{ 2.5} ) = 0.90$

=> $P( \= X > \= x ) = P( Z > z ) = 0.90$

Generally from the z-table the critical value of 0.90 is

$z = -1.282$

$\frac{\= x -45 }{ 2.5} = -1.282$

=> $\= x = 41. 795$

Considering question 2

Generally we are told that the standard deviation of the mean to be one fifth of the population standard deviation, this is mathematically represented as

$s = \frac{1}{5} \sigma$

Generally the standard deviation of the sample mean is mathematically represented as

$s = \frac{\sigma }{ \sqrt{n} }$

=> $\frac{1}{5} \sigma = \frac{\sigma }{ \sqrt{n} }$

=> $n = 5^2$

=> $n = 25$

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Answer:

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Step-by-step explanation:

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3 years ago