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1)

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-3x-2y-2z = -9                  -------------- (1)

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z = 8                               -------------- (2)

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-2x-2y-2z = -14                 -------------- (3)

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(3) ⇒ 2y = 14 - 2x - 2z      -------------- (4)

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Substitute 2y = 14 - 2x - 2z in equation(1)

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- 3x - ( 14 - 2x - 2z ) - 2z = -9

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- 3x - 14 + 2x + 2z - 2z = -9

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- x = - 9 + 14

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x = - 5

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Substitute x = - 5 , z = 8  in equation(4)

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2y = 14 - 2(-5) - 2(8)

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2y = 14 + 10 - 16

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2y = 8

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y = 4

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Solution :

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x = - 5

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y = 4

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z = 8

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2)

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x + 3y + 3z = -4                  -------------- (1)

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- 2x - 5y + z = 1                  -------------- (2)

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

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5*(1)   ⇒  5x + 15y + 15z = -20

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3*(2)   ⇒ -6x -  15y +   3z = 3

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ADDITION ___________________

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                   - x + 18z = -17

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x = 18z + 17                      -------------- (4)

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Substitute x = 18z + 17 in equation(3)

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3(18z + 17) + 5z = - 8

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54z + 51 + 5z = -8

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59z = - 8 - 51

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59z = - 59

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z = -1

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Substitute z = -1 in equation(4)

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x = 18(-1) + 17

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x = - 18 + 17

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x = -1

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Substitute x = - 1 , z = -1  in equation(1)

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-1 + 3y + 3(-1) = -4

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3y - 4 = -4

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3y = - 4 + 4

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3y = 0

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y = 0

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Solution :

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x = - 1

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y = 0

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z = - 1

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