The coefficient matrix is:
$$
\begin{bmatrix}
1 & 2 \\
-1 & 4
\end{bmatrix}
$$
The determinant D is:
$$
D = (1)(4) - (2)(-1) = 4 + 2 = 6
$$
Now, we'll find the determinants for the x and y matrices, which we'll call Dx and Dy, respectively.
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