## anonymous 4 years ago Use Cramer's rule to solve the system of equations. {x-2y=-9 3x+y=1

1. amistre64

$D,Dx,Dy$ $7,28,7$ x = -Dx/D y = Dy/D

2. amistre64

got me Dx and Dy bacwards :)

3. amistre64

7,7,28

4. amistre64

$D,Dy,Dx$ $\begin{pmatrix}1&-2\\3&1\end{pmatrix}_{1}^{(-6)}, \begin{pmatrix}1&-9\\3&1\end{pmatrix}_{1}^{(-27)}, \begin{pmatrix}-9&-2\\1&1\end{pmatrix}_{-9}^{(-2)}$ $7,28,-7$ should be it ...

5. amistre64

y= 28/7 = 4 x = -7/7 = -1 x - 2y =-9 -1 4 ---------- -1 - 9 = -9 3x +y=1 -1 4 -------- -3+4 = 1

6. amistre64

works for me :)