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3 years ago

2x+8y=6, -5x-20y=-15need work because I don't understand

Mathematics

1 answer:

Vlada [557]3 years ago

4 0

Answer:

Infinitely many solutions.

Step-by-step explanation:

Step: Solve 2x + 8y = 6 for x:

2x + 8y = 6

2x + 8y + −8y =6 + −8y (Add -8y to both sides)

2x = −8y + 6

2x/2 = (-8y + 6)/2 (Divide both sides by 2)

x = −4y + 3

Step: Substitute −4y + 3 for x in −5x − 20y = −15:

−5x − 20y = −15

−5 (−4y + 3 ) −20y = −15

−15 = −15 (Simplify both sides of the equation)

−15 + 15 = −15 + 15 (Add 15 to both sides)

0 = 0

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aivan3 [116]

Answer:

153.9 ft²

Step-by-step explanation:

The area for a circle formula is πr².

Using the radius, we get:

π×7² =

49π ≈

153.938 ≈ (Using the π key)

153.9 ft²

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4 years ago

Read 2 more answers

A pipe that is 120 cm long resonates to produce sound of wavelengths 480 cm, 160 cm, and 96 cm but does not resonate at any wave

erma4kov [3.2K]

Answer:

A Pipe that is 120 cm long resonates to produce sound of wavelengths 480 cm, 160 cm and 96 cm but does not resonate at any wavelengths longer than these. This pipe is:

A. closed at both ends

B. open at one end and closed at one end

C. open at both ends.

D. we cannot tell because we do not know the frequency of the sound.

The right choice is:

B. open at one end and closed at one end .

Step-by-step explanation:

Given:

Length of the pipe, $L$ = 120 cm

Its wavelength $\lambda_1$ = 480 cm

$\lambda_2$ = 160 cm and $\lambda_3$ = 96 cm

We have to find whether the pipe is open,closed or open-closed or none.

Note:

The fundamental wavelength of a pipe which is open at both ends is 2L.
The fundamental wavelength of a pipe which is closed at one end and open at another end is 4L.

So,

The fundamental wavelength:

⇒ $4L=4(120)=480\ cm$

It seems that the pipe is open at one end and closed at one end.

Now lets check with the subsequent wavelengths.

For one side open and one side closed pipe:

An odd-integer number of quarter wavelength have to fit into the tube of length L.

⇒ $\lambda_2=\frac{4L}{3}$ ⇒ $\lambda_3=\frac{4L}{5}$

⇒ $\lambda_2=\frac{4(120)}{3}$ ⇒ $\lambda_3=\frac{4(120)}{5}$

⇒ $\lambda_2=\frac{480}{3}$ ⇒ $\lambda_3=\frac{480}{5}$

⇒ $\lambda_2=160\ cm$ ⇒ $\lambda_3=96\ cm$

So the pipe is open at one end and closed at one end .

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3 years ago

What is an equation of a line that passes through the points (-4,8) and (2,-1)?

Evgesh-ka [11]

Answer:

y = 3/2x + 20

Step-by-step explanation:

Use point-slope form. (long to explain, it is correct though).

3 0

3 years ago

A) 2(x+3)=x-4 <br>Could anyone help?

oee [108]

If solving for x you will first need to combine like terms. Then after getting the amount of numbers and amount of x numbers you will divide the x number from both. After doing that you would get X=-10

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3 years ago

If x/y + y/x = -1 , find the value of x^3 - y^3

marin [14]

Answer:

Step-by-step explanation:

Multiplying the first equation by xy, we have ...

x^2 +y^2 = -xy

Factoring the expression of interest, we have ...

x^3 -y^3 = (x -y)(x^2 +xy +y^2)

Substituting for xy using the first expression we found, this is ...

x^3 -y^3 = (x -y)(x^2 -(x^2 +y^2) +y^2) = (x -y)(0) = 0

The value of x^3 -y^3 is 0.

7 0

3 years ago