Answer:
D) [tex]\left[\begin{array}{c}\frac{5}{4}\\-\frac{1}{2}\end{array}\right][/tex]
Step-by-step explanation:
For matrix [tex]\left[\begin{array}{cc}a&b\\c&d\end{array}\right][/tex]
the inverse matrix is the transpose of the cofactor matrix, divided by the determinant: [tex]\dfrac{1}{ad-bc}\left[\begin{array}{cc}d&-b\\-c&a\end{array}\right][/tex]
Your inverse matrix is: [tex]\dfrac{1}{2(-3)-(1)(2)}\left[\begin{array}{cc}-3&-1\\-2&2\end{array}\right][/tex]
so the solution is ...
[tex]\left[\begin{array}{c}x\\y\end{array}\right]=\left[\begin{array}{cc}\frac{3}{8}&\frac{1}{8}\\\frac{1}{4}&-\frac{1}{4}\end{array}\right] \cdot\left[\begin{array}{c}2\\4\end{array}\right] =\left[\begin{array}{c}\frac{5}{4}\\-\frac{1}{2}\end{array}\right] \qquad\text{matches selection D}[/tex]
