Thread: Cramer's rule setup question
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Old December 3rd, 2008, 11:25 AM
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Quote:
Originally Posted by mr.confused View Post
I am not sure how to solve this problem as the setup is different from other problems of this kind I have faced.All I need to know is how to set it up.If you notice the variable x is isolated on the left, usually the constant is in this position and I am not sure how to set this up.

4x= -5y+10
5x= -y-19

4x+5y=10
5x+y=-19

Find the determinant of the coefficient matrix:

D_c=\begin{vmatrix}4 & 5 \\ 5 & 1 \end{vmatrix}=-21

Now, find the determinants of the x and y matricies:

D_x=\begin{vmatrix}10 & 5 \\ -19 & 1 \end{vmatrix}=105

D_y=\begin{vmatrix}4 & 10 \\ 5 & -19 \end{vmatrix}=-126

x=\frac{D_x}{D_c}=\frac{105}{-21}=-5

y=\frac{D_y}{D_c}=\frac{-126}{-21}=6
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