3x+4＞2x+53x-2x>5-4x>1[（x-1）/2]+1≥xx-1≥2(x-1)x-1≥2x-22x-x≤-1+2x≤1所以1这不成立所以不等式组无解
3x+4＞2x+5x>12*[（x-1）/2]+2*1≥x*2x-1+2≥2x-x≥-1x≤1无解
3x+4＞2x+53x-2x>5-4x>1[（x-1）/2]+1≥xx-1+2≥2x-x≥-1x≤1无解
