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3 years ago

Can someone please explain?!

Mathematics

1 answer:

Hoochie [10]3 years ago

5 0

Infinite! You can, for example, add -1 and 1 to the equation and make it equal. In x=5, you can have x=5+1-1. and it'd still be the same. To add on to it, you could do x+1-1=5+1-1, etc..

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• Machine s is cleaned every 12 weeks. •Machine that is cleaned every 8 weeks. What is the fewest number of weeks that will pass

vfiekz [6]

Week 24,assuming that both machines are cleaned at week 0, because multiples of 12 are 12, 24,36. And multiples of 8 are 8, 16, 24. 24 is also the LCM.

7 0

3 years ago

Construct a 99% confidence interval for the population mean, mu. Assume the population has a normal distribution. A group of 1

Zarrin [17]

Answer:

99% confidence interval for the population mean is [19.891 , 24.909].

Step-by-step explanation:

We are given that a group of 19 randomly selected students has a mean age of 22.4 years with a standard deviation of 3.8 years.

Assuming the population has a normal distribution.

Firstly, the pivotal quantity for 99% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean age of selected students = 22.4 years

s = sample standard deviation = 3.8 years

n = sample of students = 19

$\mu$ = population mean

<em>Here for constructing 99% confidence interval we have used t statistics because we don't know about population standard deviation.</em>

So, 99% confidence interval for the population mean, $\mu$ is ;

P(-2.878 < $t_1_8$ < 2.878) = 0.99 {As the critical value of t at 18 degree of

freedom are -2.878 & 2.878 with P = 0.5%}

P(-2.878 < $\frac{\bar X - \mu}{\frac{s}{\sqrt{n} } }$ < 2.878) = 0.99

P( $-2.878 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X - \mu}$ < $2.878 \times {\frac{s}{\sqrt{n} } }$ ) = 0.99

P( $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ < $\mu$ < $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ) = 0.99

<u>99% confidence interval for</u> $\mu$ = [ $\bar X -2.878 \times {\frac{s}{\sqrt{n} }$ , $\bar X +2.878 \times {\frac{s}{\sqrt{n} }$ ]

= [ $22.4 -2.878 \times {\frac{3.8}{\sqrt{19} }$ , $22.4 +2.878 \times {\frac{3.8}{\sqrt{19} }$ ]

= [19.891 , 24.909]

Therefore, 99% confidence interval for the population mean is [19.891 , 24.909].

6 0

3 years ago

Identify the variable and the constant in the expression below. n + 3 variable: ___________________________ constant: __________

Ilya [14]

N is the variable and 3 is the constant.

8 0

3 years ago

(x³ + ³) / (x - y)<br> Do not include parentheses in your answer.

Lubov Fominskaja [6]

The simplified expression of $\frac{x^3 + (-y)^3}{(x - y}$ is $x^2+xy+y^2$

<h3>Complete question</h3>

Simplify the expression: (x³ + (-y)³) / (x - y)

Do not include parentheses in your answer.

<h3>How to simplify the expression?</h3>

The expression is given as:

$\frac{x^3 + (-y)^3}{(x - y}$

Open the inner bracket

$\frac{x^3 -y^3}{(x - y}$

Apply the difference of two cubes to the numerator

$\frac{(x-y)(x^2+xy+y^2)}{(x - y}$

Cancel out the common factors

$x^2+xy+y^2$

Hence, the simplified expression of $\frac{x^3 + (-y)^3}{(x - y}$ is $x^2+xy+y^2$