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2 years ago

Evaluate/simplify this problem (3 - 3i)(-6 + 3i)

Mathematics

2 answers:

mezya [45]2 years ago

6 0

Multiply using the foil method, then combine. This will give you -9+27i

igor_vitrenko [27]2 years ago

4 0

-18+9i because if you use the foil technique then this would be your answer

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10.

Kay [80]

Answer:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

Step-by-step explanation:

Information provided

$\bar X=32.1$ represent the sample mean

$\mu$ population mean

s=2.4 represent the sample standard deviation

n=83 represent the sample size

Confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

The degrees of freedom are given by:

$df=n-1=83-1=82$

The Confidence is given by 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , the critical values for this case are:

$\chi^2_{\alpha/2}=62.132$

$\chi^2_{1- \alpha/2}=104.139$

And replacing into the formula for the interval we got:

$\frac{(82)(2.4)^2}{104.139} \leq \sigma^2 \leq \frac{(82)(2.4)^2}{62.132}$

$4.535 \leq \sigma^2 \leq 7.602$

Now we just take square root on both sides of the interval and we got:

$2.2 \leq \sigma \leq 2.8$

And the best option would be:

A. 2.2 < σ < 2.8

3 0

3 years ago

Find the distance between -6 and 8

MA_775_DIABLO [31]

Answer:

Step-by-step explanation:

6+8=14

8 0

2 years ago

Read 2 more answers

Help please ASAP!!

Fittoniya [83]

Answer:

$\displaystyle 702$

Step-by-step explanation:

we are given a exponential function

$\displaystyle f(x) = {3}^{x + 1} - 22$

where x represents the number and f(x) represents the amount

we are also given that when x is 3 then f(x) is 59 likewise when x is 6 then f(x) is 2165

to figure out the average rate of change between 3 and 6 we can consider the average rate of change formula given by

$\displaystyle m = \frac{ f(x)_ {2} - f(x)_{1} }{ x_{2} - x_{1} }$

substitute what we have:

$\displaystyle m = \frac{ 2165 - 59 }{6 - 3 }$

simplify substitution:

$\displaystyle m = \frac{2106 }{3 }$

simplify division:

$\displaystyle m = 702$

hence, the average rate of change between 3 and 6 is 702

6 0

2 years ago

Read 2 more answers

Rewrite the following equation in standard form. y = -7x - 1

Lady bird [3.3K]

Standard form is written Ax + By = C where A, B, and C are all integers.

In other words, no fractions.

Also, the A or the coefficient of the x term must be positive.

The only thing we need to do is add 7x to both sides to get 7x + y = -1.

So 7x + y = -1 is our answer.

5 0

3 years ago

Read 2 more answers

Can you please help me with this?

77julia77 [94]

Answer:

first one i believe

Step-by-step explanation:

3 0

2 years ago