1.
2x＞1-x
3x>1
x>1/3
x+2＜4x-1
3x>3
x>1
大大取大
x>1
2.
x-5＞1+2x
x2
x>2
两个不能同时成立
无解
3.
2/3x+5＞1-x
5/3x>-4
x>-12/5
x-1＜3/4x-1/8
1/4x