172k views
5 votes
Find an inequality that you can use to disprove John statement. explain your thinking.

Find an inequality that you can use to disprove John statement. explain your thinking-example-1
User Bialecki
by
7.9k points

1 Answer

3 votes
Try this inequality with 0 as the right side.

-x > 0

According to John, we multiply both sides by -1, and the inequality sign does not change direction, so we get this

x > 0

Let's use a number for x that makes the original inequality true.
Let x = -2.

-x > 0

-(-2) > 0

2 > 0

As you can see, -2 does work on the original equation.

Now let's try -2 in John's solution.

x > 0

-2 > 0 which is a false statement.

Now let's solve it again, but we will reverse the inequality symbol when we multiply both sides by -1.

-x > 0

x < 0

Try x = -2.

-2 < 0 which is true

Now it works.

John is incorrect.
If you multiply or divide an equation by a negative number, even if one of its sides is 0, you still must change the direction of the inequality symbol.
User Michael Dewar
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories