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3 years ago

If f(x) = x2 + 4x - 12, find f(2).

Mathematics

1 answer:

Illusion [34]3 years ago

7 0

Answer:

-3

Step-by-step explanation:

Please write this as f(x) = x^2 + 4x - 12. "x^2" represents "the square of x."

f(2) is the value of this function when x = 2:

f(2) = f(2) = (2)^2 + 4(2) - 12 = 9 - 12 = -3

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1.8 divide by 0.72 explain

ASHA 777 [7]

Answer:

0.40

Step-by-step explanation:

Change the divisor 1.8 to a whole number by moving the decimal point 1 places to the right. Then move the decimal point in the dividend the same, 1 places to the right.

We then have the equations:

7.2 ÷ 18 = 0.40

and therefore:

0.72 ÷ 1.8 = 0.40

Both calculated to 2 decimal places.

8 0

2 years ago

Nitrates are groundwater contaminants derived from fertilizer, septic tank seepage and other sewage. Nitrate poisoning is partic

o-na [289]

Answer:

a) $n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

b) $n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

Part a

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.02$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

Since we don't have prior information about the population proportion we can use ase estimator $\hat p =0.5$ . And replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.02}{1.96})^2}=2401$

And rounded up we have that n=2401

Part b

For thi case the estimator for p is $\hat p =0.07$

$n=\frac{0.07(1-0.07)}{(\frac{0.02}{1.96})^2}=625.22$

And rounded up we have that n=626

And we see that if we have previous info about p the sample size varies a lot.

4 0

2 years ago

What is the Z-score for Paula if she got 1400 on the SAT, the mean was 1100 and the standard deviation was 275? step by step how

Setler [38]

mu = 1100 = population mean

sigma = 275 = population standard deviation

x = 1400 = raw score

z = z score

z = (x-mu)/sigma

z = (1400-1100)/(275)

z = 300/275

z = 1.0909090909091 approximately

z = 1.09

Convention is to round to two decimal places so that you can use a Z table to look up the area under the curve (which helps determine probability).

The positive z score is due to Paula's raw score being above the mean.

7 0

2 years ago

5 times as much as 16 diveded by 8

mixer [17]

The answer for this is 10

4 0

3 years ago

Read 2 more answers

The triangle is not necessarily drawn to scale, and the angles can vary. Create a compound inequality for the side length x usin

Artist 52 [7]

Answer:

Step-by-step explanation:

given 2 sides of a triangle then the third side x is in the range

difference of 2 sides < x < sum of 2 sides , that is

7 - 5 < x < 7 + 5

2 < x < 12

5 0

2 years ago