I need help 9-16!!Thank u!

Factor to find the zeros of the function defined by the quadratic expression. −7x2 − 91x − 280

Mariulka [41]

There are no zeroes for an expression, only for equations.
Assuming equation to be
<span>−7x^2 − 91x − 280=0
-7(x^2+13x+40)=0
-7(x+8)(x+5)=0
by the zero product properties,
x+8=0 => x=-8
or
x+5=0 => x=-5</span>

3 0

3 years ago

A spinner has three unusual sections: red, yellow, and blue.. The table shows the results of Nolan’s spins. Find the probability

Anika [276]

Answers:

Red = 1/3
Yellow = 7/15
Blue = 1/5

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Explanation:

Add up all the frequencies in the table to see that there are 120+168+72 = 360 spins total.

Of those 360 spins, 120 of them land on red. The probability of landing on red is 120/360 = (120*1)/(120*3) = 1/3
Since 168 land on yellow, this means the probability of landing on yellow is 168/360 = (24*7)/(24*15) = 7/15
Lastly, we have 72 occurrences of blue out of 360 total spins. The probability of landing on blue is 72/360 = (72*1)/(72*5) = 1/5

4 0

3 years ago

The Wisconsin Dairy Association is interested in estimating the mean weekly consumption of milk for adults over the age of 18 in

Stolb23 [73]

Answer:

$ME = 1.653 *\frac{7.9}{\sqrt{300}}= \pm 0.75$

±0.75 ounce

Step-by-step explanation:

Assuming this complete question: The Wisconsin Dairy Association is interested in estimating the mean weekly consumption of milk for adults over the age of 18 in that state. To do this, they have selected a random sample of 300 people from the designated population. The following results were recorded: xbar=34.5 ounces, s=7.9 ounces Given this information, if the leaders wish to estimate the mean milk consumption with 90 percent confidence, what is the approximate margin of error in the estimate?

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".

$\bar X=34.5$ represent the sample mean

$\mu$ population mean (variable of interest)

s=7.9 represent the sample standard deviation

n=300 represent the sample size

Solution to the problem

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:

$df=n-1=300-1=299$

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,199)".And we see that $t_{\alpha/2}=1.653$

And the margin of error is given by:

$ME = 1.653 *\frac{7.9}{\sqrt{300}}= \pm 0.75$

±0.75 ounce

4 0

3 years ago

Read 2 more answers

PLEASE HELP ME!!!!!!

Nata [24]

9514 1404 393

Answer:

vertex: (2, -3.2)

axis of symmetry: x = 2

zeros: x=0, x=4

formula for axis of symmetry:

x = <x-coordinate of vertex>
x = -b/(2a) . . . . . . . where the quadratic is ax^2 +bx +c
x = average of zeros, (z1 +z2)/2

Step-by-step explanation:

a) The vertex x-coordinate is halfway between the zeros, so is x = (0+4)/2 = 2. It is where the graph has a turning point.

The vertex y-coordinate is the low point of this graph. It is not on a grid line, so we can only guess at its value. I choose to call it -3.2.

The vertex is (2, -3.2).

__

b) The axis of symmetry is the vertical line through the vertex. The constant in its equation is the x-coordinate of the vertex:

x = 2

__

c) The zeros of the function are where the function crosses the x-axis. These are marked on the graph with red dots. The zeros are x=0 and x=4.

__

d) When the quadratic is written in standard form, ax^2 +bx +c, the equation of the axis of symmetry is ...

x = -b/(2a) . . . . . perhaps this is the formula you're being asked for (?)

When there is no equation, the axis of symmetry can be found from the graph a couple of ways. One is to identify the x-coordinate of the vertex.

x = <x-coordinate of the vertex>

Another is to average the zeros, since they are symmetrical about the axis of symmetry.

x = average of zeros = (z1 +z2)/2

If the quadratic is written in vertex form, the vertex coordinate is the constant in the equation for the axis of symmetry.

y = a(x -h)^2 +k . . . . . quadratic with vertex (h, k)

x = h . . . . . . equation of axis of symmetry

8 0

2 years ago

Find the probability that a randomly selected student drives to school.

Slav-nsk [51]

Answer:

the answer is 40 percent

4 0

3 years ago