b) 3x+3> sau = cu 9
3x>=9-3 |:3
x>=3-1
x>=2
=>x={2,1,0,-1,-2,-3,-4,-5,-6........}
c)5x+8*5< sau = cu 10. |:5
x+8=< 5
x= sau < 5-8
x=< -3
x={-3,-4,-5,-6,-7,-8......}
d)-2x -(-5)>4
-2x+5>4
-2x>4-5
-2x>-1. |*(-2)
2x>1
x={1,3,5,7,9,.........}
e) 3x+7>4
3x>4+7
3x>11
x={12,15,18,21,24,27,30.......}
