∵|2x-y+3t| +（ 3y+x-2t）² =0
而∵|2x-y+3t| ≥0,（ 3y+x-2t）² ≥0
∴2x-y+3t=0
3y+x-2t=0
解得x=-t
y=t
(3x+2y)/(3x-y)
=(-3t+2t)/(-3t-t)
=-t/(-4t)
=1/4