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4 years ago

F(x) = -2x2 + 7 Find f(-5)

Mathematics

2 answers:

Ainat [17]4 years ago

5 0

Answer:

f(-5) = -43

Step-by-step explanation:

Step 1: Define

f(x) = -2x² + 7

f(-5) is x = -5

Step 2: Substitute and Evaluate

f(-5) = -2(-5)² + 7

f(-5) = -2(25) + 7

f(-5) = -50 + 7

f(-5) = -43

mash [69]4 years ago

3 0

F(-5)=-43 is the answer

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In a class of 27 students, 14 play an instrument and 16 play a sport. There are 6

antiseptic1488 [7]

Answer: 1/3

Step-by-step explanation:

6 + 16 + 14 - 27 = 1/3

6 0

1 year ago

A scooter travels 18 miles in the same time a bike covers 8 miles. If the rate of the scooter is two miles per hour than twice t

blsea [12.9K]

ANSWER:

A scooter travels 18 miles in the same time a bike covers 8 miles.The rates of both scooter and bike are 8 miles per hour and 18 miles per hour

SOLUTION:

Given, a scooter travels 18 miles in the same time a bike covers 8 miles.

The rate of the scooter is two miles per hour than twice the rate of the bike

We need to find both rates of scooter and bike.

Let the speed of scooter be x and speed of bike be y.

And, time taken to travel be t.

Then, for scooter:

$\bold{distance = speed \times time}$

$18 = x \times t$

$t=\frac{18}{x}$ --- (1)

For bike:

$\bold{distance = speed \times time}$

$8=y \times t$

$\mathrm{t}=\frac{8}{y}$ --- (2)

Now, equate both (1) and (2)

$\frac{18}{x}=\frac{8}{y}$

On cross-multiplication we get

18y = 8x

4x – 9y = 0 ---- (3)

We also know that, rate of the scooter is two miles per hour than twice the rate of the bike.

x = 2 + 2y ---- (4)

Now substitute (4) in (3)

4(2 + 2y) – 9y = 0

8 + 8y – 9y = 0

9y – 8y = 8

y = 8.

Again substitute y value in (4)

x = 2 + 2(8) = 2 + 16

x = 18.

Hence, the rates of both scooter and bike are 8 and 18 miles per hour

8 0

4 years ago

A newspaper reported the results of a poll concerning topics that teenagers most want to discuss with their parents. In the the

ahrayia [7]

Answer:

Step-by-step explanation:

Confidence interval is written as

Sample proportion ± margin of error

Margin of error = z × √pq/n

Where

z represents the z score corresponding to the confidence level

p = sample proportion. It also means probability of success

q = probability of failure

q = 1 - p

p = x/n

Where

n represents the number of samples

x represents the number of success

From the information given,

n = 536

p = 37/100 = 0.37

q = 1 - 0.37 = 0.63

To determine the z score, we subtract the confidence level from 100% to get α

α = 1 - 0.99 = 0.01

α/2 = 0.01/2 = 0.005

This is the area in each tail. Since we want the area in the middle, it becomes

1 - 0.005 = 0.995

The z score corresponding to the area on the z table is 2.53. Thus, confidence level of 99% is 2.58

Therefore, the 99% confidence interval is

0.37 ± 2.58 × √(0.37)(0.63)/536

= 0.37 ± 0.054

The lower limit of the confidence interval is

0.37 - 0.054 = 0.316

The upper limit of the confidence interval is

0.37 + 0.054 = 0.424

Therefore, with 99% confidence interval, the proportion of all teenagers that want more discussions with their parents about school is between 0.316 and 0.424

3 0

3 years ago

A sample of 1000 college students at NC State University were randomly selected for a survey. Among the survey participants, 102

cupoosta [38]

Answer:

The upper endpoint of the 99% confidence interval for population proportion is 0.13.

Step-by-step explanation:

The confidence interval for population proportion is:

$CI=\hat p\pm z_{\alpha /2}\sqrt{\frac{\hat p(1-\hat p)}{n}}$

Given:

n = 1000

$\hat p$ = 0.102

$z_{\alpha /2}=z_{0.01/2}=z_{0.005}=2.58$

*Use the standard normal table for the critical value.

Compute the 99% confidence interval for population proportion as follows:

$CI=\hat p\pm z_{\alpha /2}\sqrt{\frac{\hat p(1-\hat p)}{n}}\\=0.102\pm 2.58\times\sqrt{\frac{0.102(1-0.102)}{1000}}\\=0.102\pm0.0248\\=(0.0772, 0.1268)\\\approx (0.08, 0.13)$

Thus, the upper limit of the 99% confidence interval for population proportion is 0.13.

6 0

3 years ago

Help Best answer I will mark as brainliest

icang [17]

The answer is $30 she would save 30 dollars in a 24 week period

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3 years ago

Read 2 more answers