# Inequalities, Cross Multiplication and Multiplying by Negative Numbers

1) If a < b, then -a > -b Why?

2) What role of operations that applies when you are solving an equation does not apply when you are solving an inequality?

3) What is the inherent meaning and justification of cross-multiplication as it applies to solving an inequality?

4) What is different about multiplying an equation by a negative number and multiplying an inequality by a negative number?

Â© BrainMass Inc. brainmass.com December 24, 2021, 6:56 pm ad1c9bdddfhttps://brainmass.com/math/basic-algebra/inequalities-cross-multiplication-multiplying-151545

#### Solution Preview

1) If a < b, then -a > -b Why?

This is a property of inequalities. If an inequality is multiplied (or divided) by a negative number, the sign of the inequality gets reversed. If 2 <3, then we know that

-2 > -3.

2) What role of operations that applies when you are solving an equation does not apply when you are solving an inequality?

Multiplication and Division. As stated ...

#### Solution Summary

Inequalities, cross multiplication and multiplying by negative numbers are investigated. The solution is detailed and well presented. The response was given a rating of "5/5" by the student who originally posted the question.