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2 years ago

What is the value of -3(15-s)+2s^2 when s=-3PLEASE ANSWER QUICKLY!!!!!

Mathematics

1 answer:

harina [27]2 years ago

7 0

Answer:

-36

Step-by-step explanation:

1. Plug -3 into the equation given: -3(15-(-3)+2(-3)^2

2. Use Pemdas and first distribute the negative to negative three then distribute -3 to the rest of the parenthesis (final answer): -45-9 +2(-3)^2

3. Then put -3 to the power of 2 (which is 9) then multiply it by 2 (final answer): -45-9+18

4. Combine all like terms and you get the answer -36!

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An article reported that for a sample of 52 kitchens with gas cooking appliances monitored during a one-week period, the sample

kolbaska11 [484]

Answer:

a) $654.16-2.01\frac{164.55}{\sqrt{52}}=608.29$

$654.16+2.01\frac{164.55}{\sqrt{52}}=700.03$

And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm

b) $n=(\frac{1.960(175)}{25})^2 =188.23 \approx 189$

Step-by-step explanation:

Part a

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=52-1=51$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,51)".And we see that $t_{\alpha/2}=2.01$

Replacing we got:

$654.16-2.01\frac{164.55}{\sqrt{52}}=608.29$

$654.16+2.01\frac{164.55}{\sqrt{52}}=700.03$

And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm

Part b

The margin of error is given by :

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

The desired margin of error is ME =50/2=25 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} s}{ME})^2$ (b)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025;0;1)", and we got $z_{\alpha/2}=1.960$ , and we use an estimator of the population variance the value of 175 replacing into formula (b) we got:

$n=(\frac{1.960(175)}{25})^2 =188.23 \approx 189$

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3 years ago

Irina-Kira [14]

Answer:

No.

Step-by-step explanation:

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2 years ago

A bulletin board can be covered completely by 30 square pieces of paper without any gaps or overlaps. If each piece of paper has

9966 [12]

Can you help me please I need help with a couple of questions

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3 years ago

Find x please show work if u can

MAVERICK [17]

Answer:

x is 12

Step-by-step explanation:

You can find x two different ways.

The first way is to look at the numbers on the left side. You need to find the scale factor used to get from 4 to 6.

4 x 1.5 = 6

Use this for the 8

8 x 1.5 = 12

The other way you can use is look at the number on the top triangle. You need to find the scale factor used to get from 4 to 8.

4 x 2 = 8

Use this for the 6

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3 years ago

Solve for x: 3 < x + 3 < 6

Vesnalui [34]

The answer is D. 0>3

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2 years ago