Answer :
Given:
The system of equation is
[tex]2x+y=8[/tex]
[tex]x-y=10[/tex]
To find:
The value of the system determinant.
Solution:
If two equations of a system of equations are [tex]a_1x+b_1y=c_1[/tex] and [tex]a_2x+b_2y=c_2[/tex], then the system determinant is
[tex]D=\left|\begin{matrix}a_1&b_1\\a_2&b_2\end{matrix}\right|[/tex]
[tex]D=a_1b_2-b_1a_2[/tex]
The given two equations are [tex]2x+y=8[/tex] and [tex]x-y=10[/tex].
Here, [tex]a_1=2,b_1=1,c_1=8, a_2=1,b_2=-1,c_2=10[/tex].
[tex]D=\left|\begin{matrix}2&1\\1&-1\end{matrix}\right|[/tex]
[tex]D=(2)(-1)-(1)(1)[/tex]
[tex]D=-2-1[/tex]
[tex]D=-3[/tex]
The value of the system determinant is -3. Therefore, the correct option is C.
