Combining Open Sentences

10-6Absolute Values of Products in Open Sentences

Overview

Solve absolute-value sentences whose argument is a product like |2x − 3|.

Key ideas

  • Apply the same equation/inequality rules.
  • Isolate the absolute value first if needed.
  • Always check solutions.

Worked examples

Example 1

Problem. Solve |2x − 3| = 7.

Solution. 2x − 3 = 7 or = −7 → x = 5 or x = −2.

Example 2

Problem. Solve |3x + 1| < 5.

Solution. −5 < 3x + 1 < 5 → −2 < x < 4/3.

Practice

Try each one. Click Show answer when ready.

  1. 1.

    Solve |2x + 1| = 9.

  2. 2.

    Solve |3x − 6| ≤ 9.

  3. 3.

    Solve |4x| > 8.

Challenge problems

A little tougher — great for test prep. Click Show answer when ready.

  1. 1.

    Solve: |3x| + 2 = 11.

  2. 2.

    Solve: 2|x − 1| − 3 = 5.