What is the result of applying R2←R2−2R1R_2 \leftarrow R_2 - 2R_1R2←R2−2R1 to (1224)\begin{pmatrix} 1 & 2 \\ 2 & 4 \end{pmatrix}(1224)?
(1200)\begin{pmatrix} 1 & 2 \\ 0 & 0 \end{pmatrix}(1020)
(1202)\begin{pmatrix} 1 & 2 \\ 0 & 2 \end{pmatrix}(1022)
(0024)\begin{pmatrix} 0 & 0 \\ 2 & 4 \end{pmatrix}(0204)
(1212)\begin{pmatrix} 1 & 2 \\ 1 & 2 \end{pmatrix}(1122)