+118608 I am not actually sure what you are being asked to do.
I would assume it means R2 is replaced by R2- 1/2 R1
in which case the answer would be
\(\begin{bmatrix} 4 && 3 && 0 \\ -6-2 && -3-1.5 && 12-0 \end{bmatrix}=> \begin{bmatrix} 4 && 3 && 0 \\ -8 && -4.5 && 12 \end{bmatrix}\)
