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3 years ago

Someone please help ASAP a(x) = 7x^2+4x-5, and b(x) = x - 4

Mathematics

1 answer:

masha68 [24]3 years ago

5 0

Answer:

Step-by-step explanation:

9x2 + 6x. = 3x(3x + 2). Answer: 3x(3x + 2). 2. Simplify: (-7x2 - 3x) - (4x2 - x) Solution: ... -2(2x + 5) Answer: -2(2x + 5) 8. Simplify:(8+4x)/4x. Solution: (8+4x)/4x = 4(2 + x)/4x ... Compare the above equation 3x2 – 5x + 1 =0 with ax2 + bx + c = 0

hope this helps. : )

please leave feedback if you have any questions thx

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Suppose we are interested in analyzing the weights of NFL players. We know that on average, NFL players weigh 247 pounds with a

tigry1 [53]

Answer:

$SE= \frac{\sigma}{\sqrt{n}} = \frac{47}{\sqrt{30}}= 8.58$

$ME= 1.64 *\frac{\sigma}{\sqrt{n}} = 1.64*\frac{47}{\sqrt{30}}= 14.073$

$\bar X - ME = 237- 14.073 = 222.927$

$\bar X + ME = 237+ 14.073 = 251.073$

$n=(\frac{1.640(47)}{5})^2 =237.65 \approx 238$

So the answer for this case would be n=238 rounded up to the nearest integer

Null hypothesis: $\mu \geq 247$

Alternative hypothesis: $\mu$

$z=\frac{237-247}{\frac{47}{\sqrt{30}}}=-1.165$

$p_v =P(z$

If we compare the p value and the significance level given $\alpha=0.1$ we see that $p_v>\alpha$ so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can't conclude that the true mean is lower than 247 at 10% of significance.

Step-by-step explanation:

For this case we have the following data given:

$\bar X =237$ represent the sample mean

$\sigma = 47$ represent the population deviation

$n =30$ represent the sample size selected

$\mu_0 = 247$ represent the value that we want to test.

The standard error for this case is given by:

$SE= \frac{\sigma}{\sqrt{n}} = \frac{47}{\sqrt{30}}= 8.58$

For the 90% confidence the value of the significance is given by $\alpha=1-0.9 = 0.1$ and $\alpha/2 = 0.05$ so we can find in the normal standard distribution a quantile that accumulates 0.05 of the area on each tail and we got:

$z_{\alpha/2}= 1.64$

And the margin of error would be:

$ME= 1.64 *\frac{\sigma}{\sqrt{n}} = 1.64*\frac{47}{\sqrt{30}}= 14.073$

The confidence interval for this case would be given by:

$\bar X - ME = 237- 14.073 = 222.927$

$\bar X + ME = 237+ 14.073 = 251.073$

The margin of error is given by this formula:

$ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (a)

And on this case we have that ME =5 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

Replacing into formula (b) we got:

$n=(\frac{1.640(47)}{5})^2 =237.65 \approx 238$

So the answer for this case would be n=238 rounded up to the nearest integer

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the true mean is lower than 247 pounds, the system of hypothesis would be:

Null hypothesis: $\mu \geq 247$

Alternative hypothesis: $\mu$

Since we know the population deviation, is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{237-247}{\frac{47}{\sqrt{30}}}=-1.165$

P-value

Since is a left tailed test the p value would be:

$p_v =P(z$

Conclusion

5 0

3 years ago

What is the answer to K/2+1-1k=-2k

Mazyrski [523]

$\dfrac{k}{2}+1-1k=-2k\\\\\dfrac{1}{2}k+1-k=-2k\\\\\left(\dfrac{1}{2}k-k\right)+1=-2k\\\\-\dfrac{1}{2}k+1=-2k\qquad\text{subtract 1 from both sides}\\\\-\dfrac{1}{2}k=-2k-1\qquad\text{add 2k to both sides}\\\\1\dfrac{1}{2}k=-1\qquad\text{convert the mixed number to improper fraction}\\\\\dfrac{1\cdot2+1}{2}k=-1\\\\\dfrac{3}{2}k=-1\qqua\text{multiply both sides by}\ \dfrac{2}{3}\\\\\boxed{k=-\dfrac{2}{3}}$

4 0

3 years ago

The boston celtics have won 16 nba championships over approximately 50 years. Thus it may seem reasonable to assume that in a gi

Nutka1998 [239]

We have been given that The boston celtics have won 16 nba championships over approximately 50 years. Therefore, it can be concluded that in any given year the probability of celtics winning the title will be p = 16/50 = 0.32

For Celtics to win eight straight championships in 1959, we will be required to multiply the probability of winning championship in one year to itself 8 times.

Therefore, the required probability is:

$0.32^{8}=0.0001099511627776$

Therefore, the required probability is almost 0.00011.

8 0

3 years ago

48x^2 +44x=60 which of the following could be used to find the solution to the equation above? Select all that apply

levacccp [35]

Because the polynomial has degree 2, we can assume that there are 2 solutions (roots), whether real or imaginary.

You can subtract 60 in order to put this in standard form

48x^2+44x-60 = 0

From there, just put a,b, and c into the quadratic formula and you're good to solve for your answers.

(-b+-sqrt(b^2-4ac))/2a

(-44+-sqrt(44^2-4(48)(-60)))/2(48)

Then solve.

There is probably a better way, but this should give you the two roots/solutions.

8 0

3 years ago

(10 points)What is the sum of the first ten terms of the sequence 4,-12, 36, -144...

MrRissso [65]

Answer:

Step-by-step explanation:

7 0

3 years ago