Algebra: Chapter 4, Lesson 3, page 180.
The Multiplication Property of Inequalities
The property states if `c` is POSITIVE
- if `a < b`, then `ac < bc` and
- if `a > b`, then `ac > bc`
Where `c` is NEGATIVE
- if `a < b`, then `ac > bc` and
- if `a > b`, then `ac < bc`
Following the EXACT same steps as equalities, we have learned to solve 1 step equations with inequalities. The ONLY difference is when multiplying or dividing by a NEGATIVE number, we must REVERSE the sign of the inequality for the final solution!! If we divide or multiply by a positive number, we leave the inequality sign alone.
Here are some examples from purplemath.com that have to do with inequalities with products and divisions.