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2 years ago

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A circle is described by the equation x2 + y2 + 14x + 2y + 14 = 0. What are the coordinates for the center of the circle and the

length of the radius?
A(-7, -1), 36 units
B(7, 1), 36 units
C(7, 1), 6 units
D(-7, -1), 6 units

1 answer:

TiliK225 [7]2 years ago

7 0

Hello :
<span>x² + y² + 14x + 2y + 14 = 0
</span>(x² + 14x) + (y²+ 2y) + 14 = 0
(x² + 14x+49-49) + (y²+ 2y+1-1) + 14 = 0
(x² + 14x+49)-49 + (y²+ 2y+1)-1 + 14 = 0
(x+7)² + (y+1)² =6²...(answer : <span>D(-7, -1), 6 units )</span>

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A store sells yogurt in small, medium, and large sizes. A small yogurt costs $2, a medium costs $3, and a large costs $5. In one

lidiya [134]

Let S = number of small yogurts ($2 each).
Let M = number of medium yogurts ($3 each)
Let L = number of large yogurts ($5 each)

Total yogurts is 27, therefore
S + M + L = 27

Total revenue generated is $98, therefore
2S + 3M +5L = 98

There are five more large yogurts than small yogurts, therefore
L = S + 5, or
-S + L = 5

These three equations may be written as the matrix equation
[ 1 1 1 | |S| |27|
| 2 3 5 | |M| = |98|
| -1 0 1 | |L| | 5|

The determinant of the matrix is
D = 3 - (2+5) + 3 = -1.

Solve with Cramer's Rule to obtain
S = -[27*3) - (98-25) - 15]
= 7
M = -[(98-25) - 27(2+5) + (10+98)]
= 8
L = -[15 - (10+98) + 27(3)]
= 12

Answer: 7 small, 8 medium, 12 large yogurts.

8 0

2 years ago

Which statements are true about the reflectional symmetry of a regular heptagon? Check all that apply. It has only 1 line of ref

Sav [38]

The answer is:

1- A line of symmetry will connect a vertex and a midpoint of an opposite side.

2- It has $7$ -fold symmetry.

The explanation for this answer is shown below:

1- By definition, a line of symmetry is an imaginary line that divides a figure into two equal images or equal halves. If you connect a vertex and a midpoint of an opposite side of an heptagon by drawing a line, you will obtain two equal halves.

2- An heptagon has seven vertices, therefore, based on the information mentioned above, it has $7$ -fold symmetry.

8 0

1 year ago

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The Bay Area Online Institute (BAOI) has set a guideline of 60 hours for the time it should take to complete an independent stud

yarga [219]

Answer:

At the 5% level, BAOI can infer that the average time to complete does not exceeds 60 hours.

Step-by-step explanation:

From the question we are told that

The population mean is $\mu = 60 \ hr$

The sample size is $n = 16$

The sample mean is $\= x = 68 \ hr$

The standard deviation is $\sigma = 20 \ hr$

The null hypothesis is $H_o : \mu = 60$

The alternative $H_a : \mu > 60$

Here we would assume the level of significance of this test to be

$\alpha = 5\% = 0.05$

Next we will obtain the critical value of the level of significance from the normal distribution table, the value is $Z_{0.05} = 1.645$

Generally the test statistics is mathematically represented as

$t = \frac{ \= x - \mu}{ \frac{ \sigma }{\sqrt{n} } }$

substituting values

$t = \frac{ 68 - 60 }{ \frac{ 20 }{\sqrt{16} } }$

$t = 1.6$

Looking at the value of t and $Z_{\alpha }$ we see that $t< Z_{\alpha }$ hence we fail to reject the null hypothesis

This means that there no sufficient evidence to conclude that it takes more than 60 hours to complete the course

So

At the 5% level, BAOI can infer that the average time to complete does not exceeds 60 hours.

6 0

1 year ago

A stone is dropped into a barrel of water and sinks to the bottom. The ball is completely covered by water. By how much does the

Rom4ik [11]

Answer:

Answer: 5/12 or approx. 0.42

Step-by-step explanation:

The ball will displace as much water as its volume.

Meaning, the volume of the ball and the volume of the increase in water in the barrel will be equal.

Volume of a sphere:

$V_s=\frac{4}{3} \pi r^3$

The radius is half the diameter. The diameter of the sphere is 10, thus:

$r = d/2 = 10/2 = 5$

5^3 = 5*5*5 = 25*5 = 125

$V_s=\frac{4}{3} \pi * 5^3=\frac{4}{3} \pi * 125$

The volume of a cylinder, which will be the shape of the increase in water, is the following:

$V_c=\pi r^2 h$

We know the radius r, as we know the diameter.

$r=d/2=40/2=20$

$V_c=\pi r^2 h=\pi h * 20^2 = \pi h * 400$

We are looking for the height of the cylinder, h, as that will be the height of the water rise.

Since we know these 2 volumes are the same, we'll set them equal to each other and solve the equation:

$V_s = V_c$

$\frac{4}{3} * 125 * \pi = 400 * h * \pi$

We can get rid of pi by dividing both sides by pi:

$\frac{4}{3} * 125 = 400 * h$

And now divide both sides by 400:

$\frac{4}{3} * \frac{125}{400}= h$

Just reversing it and putting h to the left:

$h = \frac{4}{3} * \frac{125}{400} = \frac{4 * 125}{3 * 400}$

I see that I can divide both the numerator and the denominator by 4:

$h =\frac{125}{3 * 100}= \frac{125}{300}$

I'll now divide both the numerator and the denominator by 25 to simplify the expression:

$h=\frac{125}{300} =\frac{125 / 25}{300 / 25} = \frac{5}{12}$

Answer: The water rises by 5/12 (five twelfths).

If I want an approximate decimal answer, I can simply run this expression in a calculator:

$\frac{5}{12}$ ≈ $0.416666667$ ≈ $0.42$

7 0

1 year ago

If HJ= 7x-27 . Find the value of x

Alinara [238K]

we are given

$HJ=7x-27$

Since, we have to solve for x

so, we will isolate x on anyone side

step-1: Add both sides 27

$HJ+27=7x-27+27$

$HJ+27=7x$

step-2: Divide both sides by 7

$HJ+27=7x$

$\frac{HJ+27}{7}= \frac{7x}{7}$

now, we can simplify it

$\frac{HJ+27}{7}= x$

$x=\frac{HJ+27}{7}$ ................Answer

7 0

2 years ago

Read 2 more answers