ab=a/2+b/3+4→3a+2b+24=6ab=3a·2b≤(3a+2b)/4 →(3a+2b-12)(3a+2b+4)≥0 →3a+2b≥12(当3a=2b,即a=2,b=3时,取最小值) ∴3a+2b∈【12,+∞)
记得采纳啊