Is an inequality, as long as there is greater than the sign, greater than or equal to the sign, less than the sign, less than or equal to the sign, not equal to the sign, are inequalities. Whether this inequality is possible.

2. The difference between m and 4 is negative, which can be expressed as that m-4 is less than 0. The negative number of a should be expressed as less than 0.

3.x is less than 0, and x+ 1 can also be less than or equal to 0. For example, when x=-2, x+ 1=- 1 is less than 0; When x+- 1, x+ 1=0.

-x is greater than 0.