There's just one important point to remember.
--Whenever you multiply or divide both sides of an inequality by a negative, the inequality sign switches directions.
Besides this rule, inequalities can be manipulated with the usual algebra tools.
Things we can do without affecting the direction of the inequality:
1. Add (or subtract) a number from both sides.
2. Multiply (or divide) both sides by a positive number.
3. Simplify a side.
