SOLUTION: X+5y-4z=20 -3x-14y+z=-25 5x-8y-2z=-20

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Question 1002471: X+5y-4z=20
-3x-14y+z=-25
5x-8y-2z=-20
Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
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X+5y-4z=20
-3x-14y+z=-25
5x-8y-2z=-20

Using the Cramer's rule
(see the lesson  Solving systems of linear equations in three unknowns using determinant (Cramer's rule)  in this site):

Determinant is  D = -345.

Dx = 690.       -----> x = Dx%2FD = 690%2F%28-345%29 = -2.

Dy = -690.       ----> y = Dy%2FD = %28-690%29%2F%28-345%29 = 2.

z = %2820+-+%28x+%2B+5y%29%29%2F%28-4%29 = %2820-%28-2%2B5%2A2%29%29%2F%28-4%29 = %2820-8%29%2F%28-4%29 = 12%2F%28-4%29 = -3.

Answer.  x = -2,  y = 2,  z = -3.