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3 years ago

Evaluate the function. f(x)=-2x^2-7x+6 Find f(−3)

Mathematics

1 answer:

Bad White [126]3 years ago

5 0

Answer:

f(-3) = 9

Step-by-step explanation:

Step 1: Define

f(x) = -2x² - 7x + 6

f(-3) = x = -3

Step 2: Substitute and evaluate

f(-3) = -2(-3)² - 7(-3) + 6

f(-3) = -2(9) + 21 + 6

f(-3) = -18 + 21 + 6

f(-3) = 3 + 6

f(-3) = 9

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What is the best interpretation of c(20) = 65 in terms of the problerm?

Levart [38]

Answer:

I think C would be 3.25

Step-by-step explanation:

Because if you divide 65/20+3.25 sorry if i'm wrong.

5 0

3 years ago

In the past, 21% of all homes with a stay-at-home parent, the father is the stay-at-home parent. An independent research firm ha

Afina-wow [57]

Answer:

A sample size of 79 is needed.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

For this problem, we have that:

$\pi = 0.21$

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

95% confidence level

So $\alpha = 0.05$ , z is the value of Z that has a pvalue of $1 - \frac{0.05}{2} = 0.975$ , so $Z = 1.96$ .

What sample size is needed if the research firm's goal is to estimate the current proportion of homes with a stay-at-home parent in which the father is the stay-at-home parent with a margin of error of 0.09?

A sample size of n is needed.

n is found when M = 0.09. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.09 = 1.96\sqrt{\frac{0.21*0.79}{n}}$