Find xxx using Cramer's rule for the system (3121)(xy)=(54)\begin{pmatrix} 3 & 1 \\ 2 & 1 \end{pmatrix} \begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix} 5 \\ 4 \end{pmatrix}(3211)(xy)=(54).
x=1x = 1x=1
x=2x = 2x=2
x=3x = 3x=3
x=0x = 0x=0