3x+y=2m-1 ……①
2x-3y=5m-8 ……②
①×3+②得
11X = 11M-11
X = M-1 ,代入①得
Y = 2M-1-3(M-1) = 2-M
则有:
M-1≥0
2-M≥0
解得1≤M≤2