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Solve for the following systems using the algebraic method.

1. 3x + 4y = 12; 2x – 3y = 6

2. x + y = 3; x – y = 5

3. 3x + 2y – z = 4; 2x – y + 3z = 4; x + y + 2z = 4

4. x – y + 5z = -4; 4x – 2y + 3z = 1; 3x – 2y + 6z = 6

5. x2 + y2 = 13; 2x – 3y = -5

6. 5x2 + y2 = 14; 3x2 – 2y2 = -15

7. 2x2 + 5x – 4y = 3; 3x2 – 3x + 2y2 = 2

User Kazy
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2 Answers

5 votes

Answer:

3x + 4y = 12; 2x – 3y = 6

Multiplying the first equation by 2 and the second equation by 3, we get:

6x + 8y = 24

6x - 9y = 18

Subtracting the second equation from the first, we get:

17y = 6

y = 6/17

Substituting y in the first equation, we get:

3x + 4(6/17) = 12

3x = 180/17 - 24/17

3x = 156/17

x = 52/17

Therefore, the solution of the given system is x = 52/17 and y = 6/17.

x + y = 3; x – y = 5

Adding the two equations, we get:

2x = 8

x = 4

Substituting x in the first equation, we get:

4 + y = 3

y = -1

Therefore, the solution of the given system is x = 4 and y = -1.

3x + 2y – z = 4; 2x – y + 3z = 4; x + y + 2z = 4

Adding the first and second equations, we get:

5x + y + 2z = 8

Subtracting the third equation from the above equation, we get:

4x + z = 4

Substituting z = 4 - 4x in the third equation, we get:

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

7x + 2y = 8

Substituting y = (8 - 7x)/2 in the first equation, we get:

9x - z = 8

Substituting z = 4 - 4x, we get:

x = 4/5, y = 2/5, and z = 4/5

Therefore, the solution of the given system is x = 4/5, y = 2/5, and z = 4/5.

x – y + 5z = -4; 4x – 2y + 3z = 1; 3x – 2y + 6z = 6

Multiplying the first equation by -4 and adding it to the second equation, we get:

16x - 6z = 17

Multiplying the first equation by -3 and adding it to the third equation, we get:

9x + 4z = 18

Multiplying the second equation by 2 and subtracting it from the third equation, we get:

x + 6z = 8

Substituting z = (8 - x)/6 in the above equation, we get:

x = 10/3, y = 8/3, and z = 2/3

Therefore, the solution of the given system is x = 10/3, y = 8/3, and z = 2/3.

x2 + y2 = 13; 2x – 3y = -5

Squaring the second equation and simplifying, we get:

4x2 - 12xy + 9y2 = 25

Adding the above equation to the first equation, we get:

5x2 + 10y2 = 38

Sub

Explanation:

User Talha Tanveer
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1 vote

Answer: Example 2: Solve the system of equations with augmented matrices using the Gauss-Jordan elimination method. x – 3z = – 2. 2x + 2y + z = 4. 3x + y – 2z = 5.

Explanation:

User Rmbianchi
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7.9k points