Section: Math Section 1

19)
X ≠ 0

Which of the following expressions describes the indicated values on the number line above ?

1. x ≥ 1
2. x ≤ 1
3. x ≥ |1|
4. |x| ≥ 1
5. |x| ≤ 1

Be sure not to be tempted by answers that are partly right. x ≥ 1 describes the right half of the values on the number line but leaves out the left half. The selected values on the number line consist of 1, everything greater than 1, -1, and everything less than -1. The easiest way to describe this set is that the absolute value of x, or its distance from zero on the number line, is greater than or equal to 1. This can be written in mathematical notation as |x| ≥ 1.