Question 239300
I can't get Cramer's Rule to work for Y. It's OK for X and Z.
the matrix is: 
1X + 3Y -1Z = 1
-2X -6Y + 1Z = -3
3X + 5Y -2Z = 4 
The Determinate is 2.
X = 2, Y = 1, Z = 1 using Cramer's Rule, but this doesn't check 
Using RREF, the solution is 2,0,1 which works. 
When I take the determinate of Y in Cramer's rule, it is not 0 which it has to be to make Y=0. 
what am I doing wrong? 
could it be that Cramer's Rule doesn't work some times?
Thanks
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Cramer's Rule always works.
If the coefficient determinant is zero it means there is no 
x,y,z point that satisfies the linear systerm.
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You have to be careful when using Cramer as a single arithmetic
error will result in a wrong answer.
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By the way, the answer is x = 2 ; y = 0, z = 1
AND the Y-determinant is zero.  Check your 
arithmetic.
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Cheers,
Stan H.