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3 years ago

F(x) = 5x2 - X+ 3 Please help

Mathematics

1 answer:

muminat3 years ago

5 0

Answer:

Step-by-step explanation:

Do you know how to use the quadratic formula?

$x = \frac{-b +/- \sqrt{b^2 - 4*a*c} }{2*a}$

a = 5

b = -1

c = 3

$x = \frac{1 +/- \sqrt{1 - 4*1*3} }{2}\\x= \frac{1 +\sqrt{-11} }{2}\\x = \frac{1 +/- i\sqrt{11} }{2}$

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An industrial expert claims that the average useful lifetime of a typical car transimssion which comes with ten years warranty i

lesya692 [45]

Answer:

a. none of these answers

Data provides sufficient evidence, at 1% significance level, to support the expert's claim. In addition the p-value (or the observed significance level) is equal to P( T >3.281)

Step-by-step explanation:

Data given and notation

$\bar X=13.5$ represent the mean height for the sample

$s=3.2$ represent the sample standard deviation for the sample

$n=9$ sample size

$\mu_o =10$ represent the value that we want to test

$\alpha=0.01$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is higher than 10 years, the system of hypothesis would be:

Null hypothesis: $\mu \leq 10$

Alternative hypothesis: $\mu > 10$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-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:

$t=\frac{13.5-10}{\frac{3.2}{\sqrt{9}}}=3.28$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=9-1=8$

Since is a one side right tailed test the p value would be:

$p_v =P(t_{(8)}>3.281)=0.00558$

Conclusion

If we compare the p value and the significance level given $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can't conclude that we have a mean higher than 10 years at 1% of significance.

a. none of these answers

3 0

3 years ago

janet is three years older than her sister julie.janets brother is eight years younger than their sister julie.the sum of all of

solniwko [45]

Let's name Janet's age x

julie is then x-3 years old

and the brother is x-3-8=x-11

and all three of them: x+x-3+x-11 are 55

so we count:

2x-3+x-11=55
3x-3-11=55
3x-14=55

add 14 5o both sides:

3x=69

divide by 3:
x=23

so Janet is 23, Julie is 23-3=20 and the brother is 20-8=12 years old!

6 0

3 years ago

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>Please explain your answer and I'll mark the Brainliest!

8_murik_8 [283]

Answer:

Step-by-step explanation:

apply sine rule 2 the triangle on left:

sinB'/10=sin45deg/8.2

sinB'=10*sin45deg/8.2=0.8623

B'=59.58deg or 120.42deg

as shown in the pic, B' > 90deg.

so B'=120.42deg.

the triangle on right has 2 sides at 8.2 so it is isosceles

B=adjacent < of B'

=180-120.42

=59.58deg

4 0

4 years ago

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Please give me an approximation of how long it would take to evacuate a population of 91,000 to a destination 21 miles away, usi

RoseWind [281]

Answer:

The time will depend on the number of people who move on each trip from the point of origin to the destination. If done at the maximum speed allowed using 100 vehicles of 50 seats each, the evacuation would be done in 63.68 hours

Step-by-step explanation:

Population = 91,000 ppl

Speed limit = 60 mph

Distance = 21 miles.

1. <em>Assuming that people is evacuated at the max. speed allowed, it means that each trip will take</em>:

T = D/V

D= 21 miles

V = 60 mph:

So;

T = 21 miles / 60mph

T= 0,35 h

2. Asumming that we are going to use an amount of 100 vehicles with 50-seats in each trip for evacuating people, it means that we could evacuate

500 people every 0,35 h ≈ 1,429 ppl/hour <em>(evacuation rate)</em>

To know how long it would take us to evacuate 91,000 people under these conditions, we would have to divide the total amount by the previously calculated evacuation rate

T= 91,000/ 1,429 = 63,68 hours

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3 years ago

There are 8 pencils in a package. How many packages will be needed for 28 children if each child gets 4 pencils?

lisov135 [29]

First, lets figure out how many pencils we will need. so we can do that by 4 pencils x 28 children and we get 112. Then if there are 8 pencils in a package, we divide 112 by 8 and get 14

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3 years ago

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