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Determine whether the following system of linear equations has no solution, only one solution, or infinitely many solutions. If the system has only one solution, find that solution.

Determine whether the following system of linear equations has no solution, only one-example-1
User Newsha
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1 Answer

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25 votes

You have the following system of equations:

3x - 3y + 3z = 0 (1)

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

-7x + 6y - 2z = -2 (3)

In order to determine if the previous system has solution or not, proceed as follow:

Add equation (1) and (2):

3x - 3y + 3z = 0

2x - y - 3z = 2

5x - 4y = 2 (5)

Multiply the equation (3) by -3 and the equation (2) by 2:

(-7x + 6y - 2z = -2)(-3)

21x - 18y + 6z = 6

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

4x -2y - 6z = 4

Add the previous results:

21x - 18y + 6z = 6

4x -2y -6z = 4

25x - 20y = 10 (6)

You can notice that equation (6) is five times equation (5). It means that there is no way of getting a solution for x or y with equations (5) and (6).

the previous situation also means that there is no solution to the system of equations.

User Mustpax
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