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3 years ago

What is the radius of a circle whose equation is x2 + y2 + 8x – 6y + 21 = 0? units

Mathematics

2 answers:

Artemon [7]3 years ago

5 0

Answer:

2 units

Step-by-step explanation:

on edg

weqwewe [10]3 years ago

4 0

To answer this, use "completing the square."

x2 + y2 + 8x – 6y + 21 = 0 becomes

x^2 + 8x + 16 - 16 + y^2 - 6y + 9 - 9 + 21 = 0

(x + 4)^2 -16 + (y - 3)^2 + 12 = 0

or (x + 4)^2 + (y - 3)^2 = 4

Since 4 = r^2, r = 2 units, and the center is at (-4, 3)

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Answer:

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For this case we know the following propoertis for the random variable X

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Part a

Since the sample size is large enough we can use the central limit distribution and the distribution for the sampel mean on this case would be:

$\bar X \sim N (\mu, \frac{\sigma}{\sqrt{n}})$

With:

$\mu_{\bar X}= 83$

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