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1 year ago

What are the rational roots for the polynomial shown below? x³ + 5x²-8r-20=0

1 answer:

3 0

$x ^{3} + 5x {}^{2} - 8 r - 20 = 0 \\ x { }^{3} + 5x {}^{2} - 8r - 20(x {}^{3} + 5x {}^{2} ) = 0 - (x {}^{3} + 5x {}^{2} ) \\ - 8r - 20 = - (x {}^{3} + 5x {}^{2} ) \\ \\ - 8r - 20 + 20 = - (x {}^{3 } + 5x {}^{2} ) + 20 \\ \\ - 8r = x {}^{3} - 5x {}^{2} + 20 \\ \\$

hope it is helpful

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There are two games involving flipping a coin. In the first game you win a prize if you can throw between 45% and 55% heads. In

Nina [5.8K]

Answer:

d) 300 times for the first game and 30 times for the second

Step-by-step explanation:

We start by noting that the coin is fair and the flip of a coin has a probability of 0.5 of getting heads.

As the coin is flipped more than one time and calculated the proportion, we have to use the sampling distribution of the sampling proportions.

The mean and standard deviation of this sampling distribution is:

$\mu_p=p\\\\ \sigma_p=\sqrt{\dfrac{p(1-p)}{N}}$

We will perform an analyisis for the first game, where we win the game if the proportion is between 45% and 55%.

The probability of getting a proportion within this interval can be calculated as:

$P(0.45$

referring the z values to the z-score of the standard normal distirbution.

We can calculate this values of z as:

$z_H=\dfrac{p_H-\mu_p}{\sigma_p}=\dfrac{(p_H-p)}{\sqrt{\dfrac{p(1-p)}{N}}}=\sqrt{\dfrac{N}{p(1-p)}}*(p_H-p)>0\\\\\\z_L=\dfrac{p_L-\mu_p}{\sigma_p}=\dfrac{p_L-p}{\sqrt{\dfrac{p(1-p)}{N}}}=\sqrt{\dfrac{N}{p(1-p)}}*(p_L-p)$

If we take into account the z values, we notice that the interval increases with the number of trials, and so does the probability of getting a value within this interval.

With this information, our chances of winning increase with the number of trials. We prefer for this game the option of 300 games.

For the second game, we win if we get a proportion over 80%.

The probability of winning is:

$P(p>0.8)=P(z>z^*)$

The z value is calculated as before:

$z^*=\dfrac{p^*-\mu_p}{\sigma_p}=\dfrac{p^*-p}{\sqrt{\dfrac{p(1-p)}{N}}}=\sqrt{\dfrac{N}{p(1-p)}}*(p^*-p)>0$

As (p*-p)=0.8-0.5=0.3>0, the value z* increase with the number of trials (N).

If our chances of winnings depend on P(z>z*), they become lower as z* increases.

Then, we can conclude that our chances of winning decrease with the increase of the number of trials.

We prefer the option of 30 trials for this game.

8 0

2 years ago

Karo-lina-s [1.5K]

3 + 8 = 12 and 8 + 3 = 12

4 0

3 years ago

How many nanometers in 66cm

makvit [3.9K]

66cm is equal to 6.6e+8 nanometers.

4 0

3 years ago

Mrs. Chip bought 2 sheets and a blanket and paid $41. Mrs. Dale bought a sheet and 4 blankets and paid $80.

Katyanochek1 [597]

Answer:

Sheet = $12
Blanket = $17

Step-by-step explanation:

Let the cost of a sheet be s and cost of a blanket be b

2s + b = 41
s + 4b = 80

From the first equation we get:

b = 41 - 2s

Substitute in the second equation

s + 4*(41 - 2s) = 80
s + 164 - 8s = 80
7s = 84
s = 12

Then

b = 41- 2*12 = 17

6 0

3 years ago

Nima uses 2/3 cup peanuts, 1/2 cup cashews, 3/4 cups pecans, and some raisinsin a recipe that makes 2 1/4 cups of trail mix. How

Lesechka [4]

Answer:

8/27 cups

Step-by-step explanation:

Nima uses 2/3 cups of peanuts to make a recipe of 2 1/4 = 9/4 cups of trail mix. If we want to find how many cups of peanuts are there per cup of trail mix, we can do a rule of three:

If 9/4 cups of trail mix need 2/3 cups of peanuts, 1 cup of trail mix need X cups of peanuts:

9/4 cups of trail mix -> 2/3 cups of peanuts

1 cup of trail mix -> X cups of peanuts

9/4 / 1 = 2/3 / X

9/4 = 2/(3*X)

3*X*9 = 4*2

27*X = 8

X = 8/27 cups

7 0

3 years ago