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White raven [17]
3 years ago
12

The equation for a circle is ​x^2 − 8x + y^2 - 2y - 8 = 0

Mathematics
1 answer:
Ivanshal [37]3 years ago
6 0

Answer:

B

Step-by-step explanation:

The equation of a circle in standard form is

(x - h)² + (y - k)² = r²

where (h, k) are the coordinates of the centre and r is the radius

To obtain this form use the method of completing the square

Given

x² - 8x + y² - 2y - 8 = 0 ( add 8 to both sides )

x² - 8x + y² - 2y = 8

add ( half the coefficient of the x/y terms )² to both sides

x² + 2(- 4)x + 16 + y² + 2(- 1)y + 1 = 8 + 16 + 1

(x - 4)² + (y - 1)² = 25 → B

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What is the length and the width of a rectangle with perimeter of 48 inches if its length is 7 inches longer than its width.
sattari [20]

Answer:

Length and the width of the rectangle is 15.5 inches and 8.5 inches respectively.

Step-by-step explanation:

Given:

Length = 7 inches + Width

=> P = 48 inches

=> L = (7 + W) inches............. (1)

Perimeter 'P' is the sum of all sides of the rectangle 2 (L + W)

∴ 48 inches = 2 (L + W) .................(2)

Substitute for L in equation (2)

∴ 48 inches = 2 [(7 + W) + W]

48 = 2[7 + 2W]

48 = 14 +4W

48 - 14 = 4W

34 = 4W

W = 8.5 inches

Recall that: Length, L = (7 + W)

∴ L = (7 + 8.5)

L = 15.5 inches

4 0
3 years ago
Read 2 more answers
If y=3x - 5, find the value of y when x = -1yn
kupik [55]

Answer:

y = 3x - 5 \\ x =  - y \\ substitute \:  - y \: in \: the \: place \: of \: x \\ y =  - 3y - 5 \\ y + 3y = 5 \\ 4y = 5 \\ y =  \frac{5}{4}

6 0
2 years ago
A county is considering rasing the speed limit on a road because they claim that the mean speed of vehicles is greater than 30 m
DochEvi [55]

Answer:

No, at alpha equals 0.10​, we do not have enough evidence to support the​ county's claim.

Step-by-step explanation:

We are given that a county is considering raising the speed limit on a road because they claim that the mean speed of vehicles is greater than 30 miles per hour.

A random sample of 15 vehicles has a mean speed of 31 miles per hour and a standard deviation of 4.7 miles per hour.

<em><u>Let </u></em>\mu<em><u> = true mean speed of the vehicles.</u></em>

SO, <u>Null Hypothesis</u>, H_0 : \mu \leq  30 miles per hour   {means that the mean speed of vehicles is lesser than or equal to 30 miles per hour}

<u>Alternate Hypothesis,</u> H_A : \mu > 30 miles per hour   {means that the mean speed of vehicles is greater than 30 miles per hour}

The test statistics that will be used here is <u>One-sample t test statistics</u> as we don't know about the population standard deviation;

                        T.S.  = \frac{\bar X -\mu}{\frac{s}{\sqrt{n} } }  ~ t_n_-_1

where, \bar X = sample mean speed of 15 vehicles = 31 mph

             s = sample standard deviation = 4.7 mph

             n = sample of vehicles = 15

So, <em><u>test statistics</u></em>  =   \frac{31-30}{\frac{4.7}{\sqrt{15} } }  ~ t_1_4

                               =  0.824

<u><em>Hence, the value of test statistics is 0.824.</em></u>

<em />

<em>Now at 0.10 significance level, the t table gives critical value of 1.345 at 14 degree of freedom for right-tailed test. Since our test statistics is less than the critical value of t as 0.824 < 1.345, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region.</em>

<em />

Therefore, we conclude that the mean speed of vehicles is lesser than or equal to 30 miles per hour which means that the county's claim is not supported.

4 0
3 years ago
Raul works for Norwalk Parking Authority and is studying the parking rates for short term parking (up to 24 hours) in a new park
In-s [12.5K]

Answer:

$48

Step-by-step explanation:

First Hour: $0+$2

Second Hour: $1+$1

Every Hour is $2

$2 times by 24 equal $48

7 0
3 years ago
Read 2 more answers
Richard receives a 3.5% commission for selling cleaning supplies. What is his commission on sales of $122,591?
konstantin123 [22]

Answer:

We have to find 3.5% $122,591

So,

122591*3.5/100=4,290.685

So, the commission will be $4,290.685

5 0
3 years ago
Read 2 more answers
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