Digital PSAT Math Practice Question 179: Answer and Explanation

Question: 179

Which of the following operations could we perform on both sides of the inequality -2x > 4 in order to make it necessary to change the direction of the inequality sign while keeping x on the left hand side of the inequality?

• A. Add 4
• B. Subtract 7
• C. Multiply by 12
• D. Divide by -2

Correct Answer: D

Explanation:

(D) Multiplying or dividing an inequality by a negative number will change the direction of the inequality sign. The other operations mentioned will not do so. Here is how it would work with dividing the expression by -2:

If you try some sample values that would work for x, such as -3 or -5, you will see that the inequality is true.