> greater than 大于
例子:x > 1 , x= 2, 3, 4...
< less than 小于
例子:x < 1 , x= 0, -1, -2...
≥ greater than or equal to 大于或等于
例子:x ≥ 1 , x= 1, 2, 3, 4...
≤ less than or equal to 小于或等于
例子:x ≤ 1 , x= 1, 0, -1, -2...
x+3 < 5 and 2-3x ≤ 5
先把 x 做主角。
x+3 < 5
x < 5-3
x < 2
.
2-3x ≤ 5
-3x ≤ 5-2
x ≥ 3/-3
x ≥ -1
除或是乘, 大于/小于方向会改变
x < 2
x ≥ -1
x = -1 , 0 , 1 [答案]