All categories

3 years ago

Find the sum and choose the correct answer.

1 answer:

7 0

To put it in the simplest words :
Get rid of the parentheses and add like so:
$2n^3 - 8n^2 + 7 + n^3 + 8n - 9
$
<span>Combine like terms
2n^3+n^3= 3n^3
-8n^2 remains the same since there are no like terms for it
8n also remains the same
-9+7=-2
Put all of the numbers together
3n^3-8n^2+8n-2
Final answer:
B - the 2nd one</span>

You might be interested in

How do I solve this inequality

Makovka662 [10]

3x+5x/4≤34
leat common multiple=4
12x+5x≤136
17x≤136
x≤136/17
x≤8

Answer: x≤8 or (-∞,8]

7 0

3 years ago

Which expression is equivalent to 36/(4 + y)?

I am Lyosha [343]

Answer:

B) 36/(y+4)

Step-by-step explanation:

Use the process of elimination.

A cannot work because we are changing the operation. Instead of dividing thirty-six by the sum of four and a number, we are dividing thirty-six by four, then adding the unknown number. This is not the same as the original expression, so we know it is not this.

Next, check C. C doesn't seem right either. Remember that, unlike multiplication and addition, you cannot flip the order in which the operation is being done and still get the same answer. C says four plus a number divided by thirty-six, which is entirely different from our original expression. So the answer is not C.

And finally, check D. D doesn't work either. With D, we are dividing thirty-six by a number, then adding it to thirty-six divided by four. This is not the same as our original expression, so D isn't it.

That leaves us with B. Does it work? Yes, because changing the y and the four still will give the same thing. And yes, because 36 is being divided by the sum of that number and four. So it is our answer.

8 0

2 years ago

The brand manager for a brand of toothpaste must plan a campaign designed to increase brand recognition. He wants to first deter

JulsSmile [24]

Answer:

1) n=114

2) n=59

3) On this case no, because if we survey just the adults of the nearest college that would be a convenience sample. And when we use "convenience sample" we have some problems associated to bias. This methodology it's not appropiate in order to have a good estimation of the parameter of interest. It's better use a random, cluster or stratified sampling.

Step-by-step explanation:

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".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

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 80% of confidence, our significance level would be given by $\alpha=1-0.80=0.2$ and $\alpha/2 =0.1$ . And the critical value would be given by:

$z_{\alpha/2}=-1.28, z_{1-\alpha/2}=1.28$

Part 1

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 $ME =\pm 0.06$ or 6% points, 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 a prior estimate of $\het p$ we can use 0.5 as a good estimate, replacing into equation (b) the values from part a we got:

$n=\frac{0.5(1-0.5)}{(\frac{0.06}{1.28})^2}=113.77$

And rounded up we have that n=114

Part 2

On this case we have a prior estimate for the population proportion and is $\hat p =0.85$ so replacing the values into equation (b) we got:

$n=\frac{0.85(1-0.85)}{(\frac{0.06}{1.28})^2}=58.027$

And rounded up we have that n=59

Part 3

On this case no, because if we survey just the adults of the nearest college that would be a convenience sample. And when we use "convenience sample" we have some problems associated to bias. This methodology it's not appropiate in order to have a good estimation of the parameter of interest. It's better use a random, cluster or stratified sampling.

5 0

3 years ago

Kate wants to buy a bike that costs $250. She has $40 saved. She will also do 5 days of yard work earning $38 for each day. Will

Alex Ar [27]

Unfortunately, Katie will be $20 short

She has $40
Plus the $38 x 5 she will be earning which is $190
$190+$40 is $230

Looks like Kate needs one more day of hard work to get her bike ; )

4 0

3 years ago

Read 2 more answers

Find the equation of the line through (6,4) and (-3,-8)

alexdok [17]

Answer:

y = 4/3x - 4

Step-by-step explanation:

to find the equation of a line with 2 points, we use the slope formula which is:

$\frac{y_2-y_1}{x_2-x_1}$

we will use (6,4) as $x_1[tex] and [tex]y_1$ and we will use (-3,-8) as $x_2[tex] and [tex]y_2$ . we plug this into the slope formula:

$\frac{-8-4}{-3-6}$

-8 - 4 = -12

-3 - 6 = -9

the slope is $\frac{-12}{-9}$

but we can simplify this further by dividing the fraction by -3

-12 / -3 = 4

-9 / -3 = 3

the simplified version of the slope is $\frac{4}{3}$

we can write this in slope-intercept form which is y =mx + b, with b being the y intercept and m being the slope

y = 4/3x + b <--- we need to solve for <em>b</em> in order to find the y intercept, so substitute x & y for a point on the line, we can use any point we are given, but for this example i will use (6,4)

4 = 4/3(6) + b < multiply 4/3 x 6

4 = 8 + b < subtract 8 from both sides

-4 = b

our y intercept would be (0,-4)

the equation looks like the following:

y = 4/3x - 4, which is our answer

3 0

3 years ago