Big Ideas Math Integrated I, 2016
BI
Big Ideas Math Integrated I, 2016 View details
3. Solving Inequalities Using Multiplication or Division
Continue to next subchapter

Exercise 2 Page 71

When the inequality symbol needs to be reversed?

Example Solution: - 2x < 10

Practice makes perfect

We want to write an inequality that is solved using the Division Property of Inequality and where the inequality symbol needs to be reversed. Let's recall the Division Property of Inequality for negative divisors.

Division Property of Inequality

When dividing each side of an inequality by the same negative number, the direction of the inequality symbol must be reversed to produce an equivalent inequality.

This means that we want to write an inequality that will be solved by dividing both sides by a negative number. Solving inequality involves isolating the variable on one side. Therefore, any inequality with negative coefficient will be solved by dividing both sides by the negative number and thus reversing the sign.
- 2x < 10
x > 10/- 2
x > - 10/2
x > - 5
Keep in mind that this is only one of infinitely many inequalities that satisfy the given requirements. Let's look at some more examples of inequalities with negative coefficient of a variable!
Inequality Divide Simplify
- 3m ≥ 15 m ≤ 15/- 3 m ≤ - 5
14 < - 7a 14/- 7 > a - 2 > a
36 ≤ - 6y 36/- 6 ≥ y - 6 ≥ y