x + 2y = 5
x - 3y = 7
What is the value of the y-determinant?

Question

x + 2y = 5
x - 3y = 7
What is the value of the y-determinant?

turingtest · Answer

cramer's rule, right?

anonymous · Answer

I believe so.

turingtest · Answer

so replace the y column on the coefficient matrix for x and y by the answer column...

turingtest · Answer

$$Ax+Cy=M$$$$Bx+Dy=N$$|dw:1374600449433:dw|

turingtest · Answer

the y matrix is found by replacing the answer column into the y column|dw:1374600632825:dw|

turingtest · Answer

you get this|dw:1374600697057:dw|which you take the determinant of

jdoe0001 · Answer

$$
\begin{matrix}
x & y\
\hline\
1 & 2 &|& \color{red}{5}\
5 & -3 & | &\color{red}{7}\
\end{matrix}
\D_y = \left\lbrack
\begin{matrix}\
1 & \color{red}{5}\
5 & \color{red}{7}\
\end{matrix}
ightbrack
$$

turingtest · Answer

you still have to take the determinant of that though I believe.

jdoe0001 · Answer

yes

jdoe0001 · Answer

S.Marie23  so, what would be the determinant of $D_y$ matrix?

jdoe0001 · Answer

hmm, actually my matrix has a typo :(

jdoe0001 · Answer

$$
\begin{matrix}
x & y\
\hline\
1 & 2 &|& \color{red}{5}\
1 & -3 & | &\color{red}{7}\
\end{matrix}\
\
\begin{matrix}\
1 & \color{red}{5}\
1 & \color{red}{7}\
\end{matrix}
$$

anonymous · Answer

jdoe would it be 2 or -2?