Question

Given the system of equations, what is the value of the y-determinant?



3x + y - 10 = 0

4x - y - 4 = 0


-28
-14
28

Answer 1

id swap ys for constants

\[\begin{vmatrix}D_x&D&D_y
\\3&-10&1
\\4&-4&-1
\end{vmatrix}\]

\[D_y=\begin{vmatrix}\cancel{D_x}&\cancel{D}&\cancel{D_y}
\\3&-10&\cancel{1}
\\4&-4&\cancel{-1}
\end{vmatrix}=3(-4)-4(-10)\]