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elixir [45]
3 years ago
8

Solve the system x + 7y = 16 and 3x - 7y = 4 for x. *

Mathematics
2 answers:
Fudgin [204]3 years ago
7 0

Answer:

x=5

Step-by-step explanation:

To start solving this, you want to solve an equation for y. I chose 3x - 7y = 4 for later purposes. Subtract 3x from both sides and divide by -7 to get y = 4 - 3x / -7. Now because we have a value for y in terms of x, plug this into the other equation, x + 7y = 16. It now should look like this: x + 7(4 - 3x / -7) = 16. Now just distribute the 7 and simplify the denominator to get x+ (-4+3x)=16. This can now be 4x +4 = 16, starting to look familiar now. Lastly subtract the 4 from both sides and divide by 4 to get x = 5. Hope this helps!

OLEGan [10]3 years ago
7 0

Answer:

x = 5

Step-by-step explanation:

Answer with full steps in picture.

Please mark Brainliest.

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6X + 8Y - 4Z = 5
pochemuha

Responder:

la solución (x, y, z) es (4.48, 4.86, -1.04)

Explicación paso a paso:

Dadas las ecuaciones simultáneas;

6X + 8Y - 4Z = 5 .... 1

1X + 2Y + 5Z = 9 ... 2

9X - 3Y + 3Z = 6 .... 3

Primero necesitamos reducir el sistema de ecuaciones

Ecuación 1 * 1

Ecuación 2 * 4

__________

6X + 8Y - 4Z = 5

4X + 8Y + 20Z = 36

Restar

6x-4x - 4z-20z = 5-36

2x-24z = 31 ... 4

también

ecuación 2 * 3

ecuación 3 * 2

_______________

1X + 2Y + 5Z = 9 * 3

9X - 3Y + 3Z = 6 * 2

_______________

3x + 6y + 15z = 27

18x - 6 años + 6z = 12

Agregar

3x + 18x + 15z + 6z = 27 + 12

21x + 21z = 39 ...... 5

Resolviendo 4 y 5

2x-24z = 31 ... 4 * 21

21x + 21z = 39 ...... 5 * 2

____________

42x - 504z = 651

42x + 42z = 78

Sustraer

-504x - 42z = 651-78

-546z = 573

z = -573/546

z = -1.05

Sustituye z = -1.05 en 4

De 4;

2x-21z = 31

2x - 21 (-1,05) = 31

2x + 22,04 = 31

2x = 31-22.04

2x = 8,96

x = 8,96 / 2

x = 4,48

Obtener y

De 2:

X + 2Y + 5Z = 9

4.48 + 2y + 5 (-1.04) = 9

2 años + 4,48-5,2 = 9

2y = 9 + 0,72

2 años = 9,72

y = 9,72 / 2

y = 4,86

Por tanto, la solución (x, y, z) es (4.48, 4.86, -1.04)

6 0
3 years ago
Over a 6 week period, the price of a gallon of gas increased by 18 cents.
Fiesta28 [93]
18 divided by 6 is 3. So 3 cents/week. Hope this helps!
6 0
3 years ago
A cylindrical metal pipe has a diameter of 20 millimeters and a height of 21 millimeters. A cylindrical hole cut out of the cent
Nina [5.8K]
<h3>Answer:</h3>
  • 21π(10)^2 – 21π(6)^2
  • 2,100π – 756π
<h3>Step-by-step explanation:</h3>

The volume of metal is the difference of the overall volume of the cylinder and the volume of the hole in it. The formula for the volume of a cylinder is ...

... V = π·r^2·h . . . . . radius r and height h

For the overall dimensions, the radius is half the diameter, so is 10 mm. The hole is said to have a radius of 6 mm. The overall "height" is 21 mm, so the volume in mm³ will be ...

... V_overall -V_hole = π(10)^2(21) -π(6)^2(21)

... = 21π·10^2 -21π·6^2 . . . . . . . matches the first selection

... = 2100π -756π . . . . . . . . . . . matches the third selection

... = 1344π . . . . . . . . . . . . . . . . doesnt' match any selection

6 0
4 years ago
Read 2 more answers
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Fantom [35]
The answer to the first question would be 1% of the purchase price and the answer to the second question would be 0.5 % of the purchase price.
8 0
3 years ago
Read 2 more answers
If a=5x^2+3x-7 and b=-3x^2-7x+5 find b-a
uranmaximum [27]

Answer:

-8x^2-10x+12

Step-by-step explanation:

first set up the problem:

(-3x^2-7x+5)-(5x^2+3x-7)

Since you are subtracting you need to distribute the (-) sign:

(-3x^2‐7x+5)(-5x^2-3x+7)

Now just combine like terms

-3x^2+(-5x^2= -8x^2

(-7x+(-3x= -10x

5+7= 12

set answer in standard form:

-8x^2-10x+12

3 0
3 years ago
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