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Solve the system of equations.

3x + 4y + 3z = 5
2x + 2y + 3z = 5
5x + y+ 3z = 3
a. (x = 13, y=-6, z = -2)
b. (x = 15, y = -8, z = -4)
c. (x = 16, y = -9,2--1)
d. (x = 14, y = -1.2--3)

User SnowBlind
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1 Answer

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Final answer:

To solve the given system of equations, we can use the method of elimination. After performing the necessary steps, we find that the solution of the system is (x = 11, y = -5.5, z = -15.5).

Step-by-step explanation:

To solve the given system of equations:

3x + 4y + 3z = 5

2x + 2y + 3z = 5

5x + y + 3z = 3

We can use the method of elimination to find the values of x, y, and z.

1. Multiply the second equation by 2 and subtract it from the first equation:

(3x + 4y + 3z) - 2(2x + 2y + 3z) = 5 - 2(5)

x + 4y + 3z - 4x - 4y - 6z = 5 - 10

-x - 3z = -5

2. Multiply the third equation by 3 and subtract it from the first equation:

(3x + 4y + 3z) - 3(5x + y + 3z) = 5 - 3(3)

x + 4y + 3z - 15x - 3y - 9z = 5 - 9

-14x + y - 6z = -4

3. Multiply the third equation by 2 and subtract it from the second equation:

(2x + 2y + 3z) - 2(5x + y + 3z) = 5 - 2(3)

2x + 2y + 3z - 10x - 2y - 6z = 5 - 6

-8x - 3z = -1

4. Now we have a system of two equations:

-x - 3z = -5

-8x - 3z = -1

5. Add the two equations together:

(-x - 3z) + (-8x - 3z) = (-5) + (-1)

-9x - 6z = -6

6. Divide both sides of the equation by -3:

-9x - 6z = -6

3x + 2z = 2

7. Now substitute the value of z from the second equation into the first equation:

-x - 3z = -5

-x - 3(-2) = -5

-x + 6 = -5

-x = -5 - 6

-x = -11

x = 11

8. Substitute the values of x and z into the second equation:

3x + 2z = 2

3(11) + 2z = 2

33 + 2z = 2

2z = 2 - 33

2z = -31

z = -31/2

z = -15.5

9. Substitute the values of x and z into the third equation:

5x + y + 3z = 3

5(11) + y + 3(-15.5) = 3

55 + y - 46.5 = 3

y - 46.5 = 3 - 55

y - 46.5 = -52

y = -52 + 46.5

y = -5.5

Therefore, the solution to the system of equations is (x = 11, y = -5.5, z = -15.5).

User EricRobertBrewer
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