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3 years ago

5

A DJ has a total of 1075 dance, rock, and country songs on her system. The dance selection is three times the size of the rock s

election. The country selection has 105 more songs than the rock selection. How many songs on the system are dance? rock? country?

1 answer:

Alexus [3.1K]3 years ago

7 0

582 dance, 194 rock, 299 country.

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A race car is traveling at a constant speed of 200 miles per hour ( mph). How many miles will it travel in three hours?

german

Answer:

600 miles.

Step-by-step explanation:

You just multiply 200 by three.

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3 years ago

Read 2 more answers

A rectangle has a height of 3p^2+13p

frozen [14]

Answer:

-5p+7p^3

Step-by-step explanation: A rectangle has a height of 3p^2+13p

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+13, p, squared, plus, 1 and a width of p^3+4p

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+4p, cubed, plus, 4. we onnat

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2 years ago

Tamara rewrote the expression 0.2(4+1.4y - 2.1). Her steps are shown.

grin007 [14]

Answer:

Her first mistake was in Step 2. She added 0.2 to each term instead of multiplying by 0.2.

Step-by-step explanation:

CORRECT WAY:

0.2(4+1.4y - 2.1)

0.8 + 0.28y - 0.42

0.8 - 0.42 + 0.28y

0.38 + 0.28y

WHAT TAMARA DID:

0.2(4+1.4y - 2.1)

How she got 4.2: 0.2 + 4 = 4.2

How she got 1.6y: 0.2 + 1.4y = 1.6y

How she got -1.9: 0.2 + -2.1 = -1.9

WHAT SHE DID HERE IS WRONG. REMEMBER WHEN IT IS __( ______) IT MEANS THAT YOU NEED TO MULTIPLE NUMBER OUTSIDE THE PARATNESS TO EVERY NUMBER THAT IS INSIDE THE PARATNESS.

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2 years ago

Part 4: Use the information provided to write the vertex formula of each parabola.

sergey [27]

Answer: 1. x = (y - 2)² + 8

$\bold{2.\quad x=-\dfrac{1}{2}(y-10)^2}+1$

3. y = 2(x +9)² + 7

<u>Step-by-step explanation:</u>

Notes: Vertex form is: y =a(x - h)² + k or x =a(y - k)² + h

(h, k) is the vertex
point of vertex is midpoint of focus and directrix: $\dfrac{focus+directrix}{2}$

$\bullet\quad a=\dfrac{1}{4p}$

p is the distance from the vertex to the focus

1)

$focus = \bigg(\dfrac{-31}{4},2\bigg)\qquad directrix: x=\dfrac{-33}{4}\\\\\text{Since directrix is x, then the x-value of the vertex is:}\\\\\dfrac{focus+directrix}{2}=\dfrac{\frac{-31}{4}+\frac{-33}{4}}{2}=\dfrac{\frac{-64}{4}}{2}=\dfrac{-16}{2}=-8\\\\\text{The y-value of the vertex is given by the focus as: 2}\\\\\text{vertex (h, k)}=(-8,2)$

Now let's find the a-value:

$p=focus-vertex\\\\p=\dfrac{-31}{4}-\dfrac{-32}{4}=\dfrac{1}{4}\\\\\\a=\dfrac{1}{4p}=\dfrac{1}{4(\frac{1}{4})}=\dfrac{1}{1}=1$

Now, plug in a = 1 and (h, k) = (-8, 2) into the equation x =a(y - k)² + h

x = (y - 2)² + 8

***************************************************************************************

2)

$focus = \bigg(\dfrac{1}{2},10\bigg)\qquad directrix: x=\dfrac{3}{2}\\\\\text{Since directrix is x, then the x-value of the vertex is:}\\\\\dfrac{focus+directrix}{2}=\dfrac{\frac{1}{2}+\frac{3}{2}}{2}=\dfrac{\frac{4}{2}}{2}=\dfrac{2}{2}=1\\\\\text{The y-value of the vertex is given by the focus as: 10}\\\\\text{vertex (h, k)}=(1,10)$

Now let's find the a-value:

$p=focus-vertex\\\\p=\dfrac{1}{2}-\dfrac{2}{2}=\dfrac{-1}{2}\\\\\\a=\dfrac{1}{4p}=\dfrac{1}{4(\frac{-1}{2})}=\dfrac{1}{-2}=-\dfrac{1}{2}$

Now, plug in a = -1/2 and (h, k) = (1, 10) into the equation x =a(y - k)² + h

$\bold{x=-\dfrac{1}{2}(y-10)^2}+1$

***************************************************************************************

3)

$focus = \bigg(-9,\dfrac{57}{8}\bigg)\qquad directrix: y=\dfrac{55}{8}\\\\\text{Since directrix is y, then the y-value of the vertex is:}\\\\\dfrac{focus+directrix}{2}=\dfrac{\frac{57}{8}+\frac{55}{8}}{2}=\dfrac{\frac{112}{8}}{2}=\dfrac{14}{2}=7\\\\\text{The x-value of the vertex is given by the focus as: -9}\\\\\text{vertex (h, k)}=(-9,7)$

Now let's find the a-value:

$p=focus-vertex\\\\p=\dfrac{57}{8}-\dfrac{56}{8}=\dfrac{1}{8}\\\\\\a=\dfrac{1}{4p}=\dfrac{1}{4(\frac{1}{8})}=\dfrac{1}{\frac{1}{2}}=2$

Now, plug in a = 2 and (h, k) = (-9, 7) into the equation y =a(x - h)² + k

y = 2(x +9)² + 7

4 0

3 years ago

Help me fast i need help a lot :3

Shtirlitz [24]

the third option

because 1/3 is not equal to three

where as if we replace the x with one in all the other we would find that the equation is correct.

8 0

3 years ago