Question

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

Answer 1

\[D,Dx,Dy\]
\[7,28,7\]
x = -Dx/D
y = Dy/D

Answer 2

got me Dx and Dy bacwards :)

Answer 3

7,7,28

Answer 4

\[D,Dy,Dx\]
\[
\begin{pmatrix}1&-2\\3&1\end{pmatrix}_{1}^{(-6)},
\begin{pmatrix}1&-9\\3&1\end{pmatrix}_{1}^{(-27)},
\begin{pmatrix}-9&-2\\1&1\end{pmatrix}_{-9}^{(-2)}
\]
\[7,28,-7\]

should be it ...

Answer 5

y= 28/7 = 4
x = -7/7 = -1



x - 2y =-9
-1 4
----------
-1 - 9 = -9


3x +y=1
-1 4
--------
-3+4 = 1

Answer 6

works for me :)