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3 years ago

Someone please please help me with this!! And I will mark you as brainlist

Mathematics

1 answer:

rusak2 [61]3 years ago

8 0

Answer:

$f(x) = -x{}^{2}+3x-1\\=-(- 2)^{2} + 3(- 2) -1\\=4+(-6) - 1\\= -2-1\\=3$

$f(x) = - x {}^{2} + 3x - 1\\= -(2){}^{2} + 3(2) -1\\ =- 4 + 6 - 1\\ = - 2 - 1\\= 1$

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X^3-13x^2+40x=0 quadratic

lutik1710 [3]

Answer:

x(x-5)(x-8)

x=5

x=8

Step-by-step explanation:

x(x^2-13x+40)
x(x-5) (x-8)

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3 years ago

Evaluate each expression please help(the crossed out ones are irrelevant)

olga nikolaevna [1]

9. 31 + 5 = 36
10. 16 - 4 = 12
12. 9
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15. -539 ???
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3 years ago

The brand manager for a brand of toothpaste must plan a campaign designed to increase brand recognition. He wants to first deter

VMariaS [17]

Answer:

He must survey 123 adults.

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 z-score that has a p-value of $1 - \frac{\alpha}{2}$ .

The margin of error is:

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

Assume that a recent survey suggests that about 87% of adults have heard of the brand.

This means that $\pi = 0.87$

90% confidence level

So $\alpha = 0.1$ , z is the value of Z that has a p-value of $1 - \frac{0.1}{2} = 0.95$ , so $Z = 1.645$ .

How many adults must he survey in order to be 90% confident that his estimate is within five percentage points of the true population percentage?

This is n for which M = 0.05. So

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

$0.05 = 1.645\sqrt{\frac{0.87*0.13}{n}}$

$0.05\sqrt{n} = 1.645\sqrt{0.87*0.13}$

$\sqrt{n} = \frac{1.645\sqrt{0.87*0.13}}{0.05}$

$(\sqrt{n})^2 = (\frac{1.645\sqrt{0.87*0.13}}{0.05})^2$

$n = 122.4$

Rounding up:

He must survey 123 adults.

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3 years ago

Find a pair of integers with a product of -84 and a sum of 5.

Damm [24]

Answer:

12 x -7 = -84 12 + (-7) = 5

Step-by-step explanation:

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3 years ago

Pat is three times as old as she was 14 years ago. In seven years, she will be four times as old as she was 14 years ago. How ol

vekshin1

The answer is 21 Hope this helps

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3 years ago