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3 years ago

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Can someone help me, please?solve for

1" title="\sqrt{-9k}=\sqrt{16-k}" alt="\sqrt{-9k}=\sqrt{16-k}" align="absmiddle" class="latex-formula">

1 answer:

ahrayia [7]3 years ago

5 0

Answer:

k = -2.

Step-by-step explanation:

Squaring both sides -9k = 16 - k

Add k to both sides:

-8k = 16

Divide both sides by -8:

k = -2.

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24 points! need asap

Gnoma [55]

Answer:

a. DC

b. B

c. ED

8 0

3 years ago

Read 2 more answers

The authors of a paper describe an experiment to evaluate the effect of using a cell phone on reaction time. Subjects were asked

Serggg [28]

Answer:

a) The 99% confidence interval would be given by (24.409;24.979)

b) n=464

Step-by-step explanation:

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Part a

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

In order to calculate the critical value $t_{\alpha/2}$ we need to find first the degrees of freedom, given by:

$df=n-1=47-1=46$

Since the Confidence is 0.95 or 95%, the value of $\alpha=0.05$ and $\alpha/2 =0.025$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,46)".And we see that $t_{\alpha/2}=2.01$

Now we have everything in order to replace into formula (1):

$525-2.01\frac{75}{\sqrt{47}}=503.01$

$525+2.01\frac{75}{\sqrt{47}}=546.99$

So on this case the 95% confidence interval would be given by (503.01;546.99)

Part b

The margin of error is given by this formula:

$ME=t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

And on this case we have that ME =7 msec, we are interested in order to find the value of n, if we solve n from equation (1) we got:

$n=(\frac{t_{\alpha/2} s}{ME})^2$ (2)

The critical value for 95% of confidence interval is provided, $t_{\alpha/2}=2.01$ from part a, replacing into formula (2) we got:

$n=(\frac{2.01(75)}{7})^2 =463.79 \approx 464$

So the answer for this case would be n=464 rounded up to the nearest integer

8 0

3 years ago

Learning Task 1: Write and answer the following in your answer sheet

Marina CMI [18]

Answer:

Evaluating Polynomials:

a. f(1) = -10

b. f(-3) = -239

c. f(2)² = 3125

Factoring Polynomials:

a. (x + 1)(x² - 5x + 6) = (x + 1)(x - 3)(x - 2)

b. (x² - x - 6)(x² + 6x + 9) = (x - 3)(x + 2)(x + 3)(x + 3)

c. x³ + 3x² - 4x - 12 = (x + 3)(x - 2)(x + 2)(x - 2)(x + 2)

4 0

2 years ago

Write the equation for the graph below.<br> PLEASE I NEED HELP !

mrs_skeptik [129]

Y= 1x+ 3
1x is the slope and 3 is the y intercept
I did rise over run to find the slope 3/3=1
Y is 3 because y intercept is when a line go through the y axis and it’s on 3
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3 years ago

(x-6)² + (x + 5)² = 16

Phoenix [80]

Answer:

answer A : (2 -5)

Step-by-step explanation:

the midipoint P,Q is the center A of this circle (because PQ is a diameter)

use : (x-6)²+(x+5)² = 16 you have : A(6 , -5) now let Q(x,y) :

(x+10)/2 = 6

(y-5)/2 = - 5

x+10 = 12

y-5 = -10

so : x = 2 and y = - 5....answer A : (2 -5)

6 0

3 years ago