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2 years ago

How to solve 28,32and34

Mathematics

1 answer:

EastWind [94]2 years ago

4 0

28.) -3 | r + 4| = -21...divide both sides by -3
| r + 4 | = -21/-3
| r + 4 | = 7

r + 4 = 7 -(r + 4) = 7
r = 7 - 4 -r - 4 = 7
r = 3 -r = 7 + 4
-r = 11
r = -11

solution is : r = 3 or r = -11
=======================
32. ) 4| 7y + 2 | - 8 = -7....add 8 to both sides
4 | 7y + 2 | = -7 + 8
4| 7y + 2 | = 1 ...divide both sides by 4
| 7y + 2 | = 1/4

7y + 2 = 1/4 -(7y + 2) = 1/4
7y = 1/4 - 2 -7y - 2 = 1/4
7y = 1/4 - 8/4 -7y = 1/4 + 2
7y = -7/4 -7y = 1/4 + 8/4
y = -7/4 * 1/7 - 7y = 9/4
y = - 7/28 reduces to - 1/4 y = 9/4 * -1/7
y = - 9/28

solution is : y = -1/4 or y = -9/28
=========================
34.) I cant see this one

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3 years ago

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2 years ago

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dem82 [27]

Answer:

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Step-by-step explanation:

Given that:

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The initial activity to carry out is to determine the limits of the region

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$x =\dfrac{y}{9}$

As such,x lies between 0 to $\dfrac{y}{9}$

Given curve x = 0 , $x =\dfrac{y}{9}$ and z = 0, $y^2 + z^2 = 81$

y = 0 and

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∴ y lies between 0 and 9

Then $I = \int^9_{y=0} \int^{\dfrac{y}{9}}_{x=0} \int^{\sqrt{81-y^2}}_{z=0} \ zdzdxdy$

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$I = \int^9_{y=0} \begin {bmatrix} \dfrac{{81x -xy^2} }{2} \end {bmatrix} ^{\dfrac{y}{9}}_{0} \ dy$

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$I = \int^9_{y=0} \begin {bmatrix} \dfrac{{81 \ y -y^3} }{18} \end {bmatrix} \ dy$

$I = \dfrac{1}{18} \int^9_{y=0} \begin {bmatrix} {81 \ y -y^3} \end {bmatrix} \ dy$

$I = \dfrac{1}{18} \begin {bmatrix} {81 \ \dfrac{y^2}{2} - \dfrac{y^4}{4}} \end {bmatrix}^9_0$

$I = \dfrac{1}{18} \begin {bmatrix} {40.5 \ (9^2) - \dfrac{9^4}{4}} \end {bmatrix}$

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3 years ago

A where and a cylinder have the same radius and height . The volume of the cylinder is 48 cm 3. What is the volume of the sphere

SOVA2 [1]

Given:

Sphere and cylinder have same radius and height.

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The volume of the sphere.

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Radius and height of cylinder are equal.

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$V=\pi r^2h$

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$48=\pi r^3$

$48=3.14 \times r^3$

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3 years ago

Vivian has a 550 page book on folk tales . If she reads 9 pages everyday before falling asleep . how many days will it take her

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Answer:

62 days

Step-by-step explanation:

Given that she reads 9 pages everyday before falling asleep. Then, on day one, she would read 9m pages.

On day 2, she would read another 9 pages, making 18 pages after 2 days. If she will finish the book in x days then

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2 years ago