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3 years ago

If f(x)=3x^2+7x-8 then what does f(-3)=

Mathematics

1 answer:

Feliz [49]3 years ago

6 0

Answer:

f ( -3) = -2

Step-by-step explanation:

In pic

(Credits: Symbolab)

(Hope this helps can I pls have brainlist (crown)☺️)

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What are the coordinates of the shadow cast on the xy plane by a small object placed at the point (10,7,20) assuming that the su

BigorU [14]

We are given with two coordinates
(10, 7, 20) and
(5, 3, -2)
Which can be used to create a linear equation represented by vectors
<x, y, z> = <x0, y0, z0> + t<mx, my, mz>
We can get the slope by
<mx, my, mz> = <10, 7, 20> - <5, 3, -2> = <5, 4, 22>

<x, y, z> = <x0, y0, z0> + t<5, 4, 22>
At z = 0, and using the coordinates of either of the two points, the coordinates o the shadow of the point can be determined.

3 0

3 years ago

Make a Graph Ms. McGill has 8 containers of liquid in her refrigerator. Three of the containers hold a pint. 38 of

timurjin [86]

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7 0

3 years ago

The percentage of body fat of a random sample of 36 men aged 20 to 29 found a sample mean of 14.42. Find a 95% confidence interv

Rina8888 [55]

Answer:

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

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".

$\bar X=14.42$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=6.95$ represent the population standard deviation

n=36 represent the sample size

Solution to the problem

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

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

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: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

Now we have everything in order to replace into formula (1):

$14.42-1.96\frac{6.95}{\sqrt{36}}=12.150$

$14.42+ 1.96\frac{6.95}{\sqrt{36}}=16.690$

So on this case the 95% confidence interval would be given by (12.150;16.690)

5 0

4 years ago

A random sample of 7 fields of durum wheat has a mean yield of 29.8 bushels per acre and standard deviation of 3.62 bushels per

meriva

Answer:

CI = 29.8 ± 3.53

Critical value is z = 2.58

Step-by-step explanation:

First of all let's find margin of error. It is given by the formula;

ME = zσ/√n

We are given;

Standard deviation; σ = 3.62

Sample size; n = 7

Mean; x¯ = 29.8

Now, z-value for 99% Confidence level is 2.58

Thus;

ME = (2.58 × 3.62)/√7

ME = 3.53

CI is written as;

CI = x¯ ± ME

CI = 29.8 ± 3.53

Critical value is z = 2.58

5 0

3 years ago

At higher elevations water boils at lower temperatures. The temperature at which water boils is called the boiling point of wate

Irina-Kira [14]

Answer:

The boiling point of water is between 84 °C and 88 °C when the elevation is between 3.4 and 4.6 km.

Step-by-step explanation:

You want x such that ...

84 ≤ B(x) ≤ 88

84 ≤ 100 -3.5x ≤ 88 . . . . substitute for B(x)

-16 ≤ -3.5x ≤ -12 . . . . . . . .subtract 100

4.6 ≥ x ≥ 3.4 . . . . . . . . . . .divide by -3.5; this reverses the inequality

4 0

3 years ago