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3 years ago

8th grade pre-algebra help?! I think the answer is C, but I'm just verifying.

Mathematics

2 answers:

Lyrx [107]3 years ago

7 0

It is A. the square root of 50 is not 25

klio [65]3 years ago

3 0

Yes, the answer is A. If you multiply 25 by 25 its is not 50 it is 625

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Which coordinate plane shows the graph of the function y = ?

Brilliant_brown [7]

Y=1/2 x so graph B i think.

5 0

3 years ago

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The surface area of a right cone is 400.2 m2. The radius of the cone is 6.0 m. Determine the height of the cone to the nearest m

svetoff [14.1K]

S = πr(r + √(h² + r²))
  400.2 = 3.14(6)(6 + √(h² + 6²))
  400.2 = 18.84(6 + √(h² + 36))
  18.84   18.84
  21¹⁰⁹/₄₇₁ = 6 + √(h² + 36))
  - 6 - 6
  15¹⁰⁹/₄₇₁ = √(h² + 36)
231²²¹⁰⁰⁵/₂₂₁₈₄₁ = h² + 36
- 36   - 36
195²²¹⁰⁰⁵/₂₂₁₈₄₁ = h²
  14 ≈ h

8 0

3 years ago

Find the value of k for which the line y = kx + 6 is a tangent to the curve x^2 + y^2 – 10x + 8y = 84

guajiro [1.7K]

Answer:

k = 1/2

Step-by-step explanation:

input y = kx +6 into the equation of the curve x² + y² – 10x + 8y = 84

x² + (kx + 6)² - 10x + 8(kx + 6) = 84

expand:

x² + k²x² + 12kx + 36 - 10x + 8kx + 48 = 84

simplify by collecting like terms:

x² + k²x² + 20kx - 10x + 84 = 84

subtract 84 on both sides to bring it to the left:

x² + k²x² + 20kx - 10x + 84 - 84 = 0

x² + k²x² + 20kx - 10x = 0

factorise out x:

x²(1 + k²) + x(20k - 10) = 0

using the discriminant b² - 4ac where b is 20k - 10, a is 1 + k² and c is 0, substitute them in the formula b² - 4ac:

b² - 4ac

(20k - 10)² - 4(1 + k²)(0) = 0

the part highlighted in bold is gone because it's all multiplied by 0, so we are left with (20k - 10)² = 0

(20k - 10)² is the same as

(20k - 10)(20k - 10)

equate both to 0

20k - 10 = 0 and 20k - 10 = 0

add 10 on both sides

20k = 10 and 20k = 10

divide 20 on both sides

k = 10/20 and k = 10/20 which are both the same

10/20 is simplified to 1/2

k = 1/2

5 0

2 years ago

Adrian is a songwriter who collects royalties on his songs whenever they are played in a commercial or movie. Adrian will earn $

gayaneshka [121]

Answer:

Adrian's songs played on 9 commercials and 5 movies.

Step-by-step explanation:

Let x denotes number of commercials and y denotes number of movies.

Total number of commercials and movies = 14

So,

$x+y=14\\x=14-y\,\,\,\,...(i)$

Adrian will earn $40 every time one of his songs is played in a commercial and he will earn $130 every time one of his songs is played in a movie

Total amount earned = $1010

$40x+130y=1010\,\,\,...(ii)$

Put $x=14-y$ in (ii)

$40(14-y)+130y=1010\\560-40y+130y=1010\\90y=1010-560\\90y=450\\y=\frac{450}{90}=5$

Put $y=5$ in $x=14-y$

$x=14-5=9$

Therefore, Adrian's songs played on 9 commercials and 5 movies.

7 0

3 years ago

Which of the following is the solution of 5x – 6 = 44?

nata0808 [166]

Answer:

x = 10

Step-by-step explanation:

5x - 6 = 44

Add 6 on both sides of the equation.

5x = 50

Divide by 5 on both sides of the equation.

x = 10

So, the value of x is equal to 10

7 0

3 years ago

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