∵▏2m-(n+(4n-3(m+2n)+6m)-5n)▏
=▏2m-n-4n+3m+6n-6m+5n▕
=▏﹙2+3-6﹚m+﹙-1-4+5+6﹚n▕
=▏-m+6n▕
∴▏-m+6n▕=▏-2/3+6×﹙-4﹚▕=74/3