5x+4y=2m+1-----(1)
2x+3y=m--------(2)
(1)×3-(2)×4
15x-8x=3(2m+1)-4m
7x=2m+3
x=(2m+3)/7
(2)×5-(1)×2
15y-8y=5m-2(2m+1)
7y=m-2
y=(m-2)/7
交点在第四象限,所以有x>0,y<0
(2m+3)/7>0
(m-2)/7<0
解得-3/2选D