Which statement is true about

Answer the questions below about the quadratic function.f(x) = -2x² - 4x

Juli2301 [7.4K]

We are given the function below;

$f(x)=-2x^2-4x$

PART A

We then proceed to find if the function has a minimum or maximum value. To find if the function has a minimum or maximum value. If the x^2 coefficient is positive, the function has a minimum. If it is negative, the function has a maximum.

ANSWER: From the above, we can see that x^2 is negative, hence the function has a maximum

PART B and C

To find the minimum or maximum value, we would plot the graph of the f(x). The graph can be seen below.

From the graph, the black point helps answer part A and part B.

ANSWER: The function's maximum value is f(x)=2.

This is the point where the slope of the graph is equal to zero

ANSWER: The maximum value then occurs at x= -1

We can also solve this by differentiating the function.

$\begin{gathered} f(x)=-2x^2-4x \\ f^{\prime}(x)=-4x-4 \\ At\xi maxmum\text{ }f^{\prime}(x)=0 \\ -4x-4=0 \\ -4x=4 \\ x=-\frac{4}{4} \\ x=-1 \\ \therefore\text{The max}imum\text{ value occurs at x=-1} \\ \text{Inserting the value of x into the function, we have} \\ f(x)=-2(-1)^2-4(-1) \\ f(x)=-2+4 \\ f(x)=2 \\ \therefore\text{The function max}imum\text{ value is 2} \end{gathered}$

5 0

1 year ago

Solve the following systems of 3-variable linear equations.<br><br><br><br>50 points

Natali [406]

Answer:

x = 9/25

y = 7/25

z = 4/25

Step-by-step explanation:

2x + y = 1 .......(1)

3y + z = 1 ........(2)

x + 4z = 1 ........(3)

Elimination 1 and 2

2x + y = 1 | ×3 |

3y + z = 1 | ×1 |

6x + 3y = 3

3y + z = 1

___________--

6x - z = 2 .............. (4)

Elimination 3 and 4

x + 4z = 1 | ×6 |

6x - z = 2 | ×1 |

6x + 24z = 6

6x - z = 2

___________--

25z = 4

z = 4/25

Elimination 3 and 4

x + 4z = 1 | ×1 |

6x - z = 2 | ×4 |

x + 4z = 1

24x - 4z = 8

___________+

25x = 9

x = 9/25

Subsitution 1

2x + y = 1

2(9/25) + y = 1

18/25 + y = 1

y = 1 - 18/25

y = 25/25 - 18/25

y = 7/25

7 0

2 years ago

CAN SOMEONE HELP ME WITH THIS?!?!

Nat2105 [25]

.......................:)

7 0

3 years ago

Read 2 more answers

Suppose the standard deviation of a normal population is known to be 3, and H0 asserts that the mean is equal to 12. A random sa

blagie [28]

Answer:

$z=\frac{12.95-12}{\frac{3}{\sqrt{36}}}=1.9$

$p_v =P(z>1.9)=0.0287$

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is higher than 12 at 5% of signficance.

Step-by-step explanation:

Data given and notation

$\bar X=12.95$ represent the sample mean

$\sigma=3$ represent the population standard deviation for the sample

$n=36$ sample size

$\mu_o =12$ represent the value that we want to test

$\alpha=0.05$ represent the significance level for the hypothesis test.

z 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 equal to 12, the system of hypothesis would be:

Null hypothesis: $\mu \leq 12$

Alternative hypothesis: $\mu > 12$

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:

$z=\frac{12.95-12}{\frac{3}{\sqrt{36}}}=1.9$

P-value

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

$p_v =P(z>1.9)=0.0287$

Conclusion

If we compare the p value and the significance level given $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is higher than 12 at 5% of signficance.

4 0

3 years ago

Read 2 more answers

I need help for both!!!!!!!!!!!!!!!!!!

horrorfan [7]

It doesnt show uppppppp

4 0

3 years ago