SAT and ACT math terms · SAT Math, ACT Math
Absolute value
Absolute value: The distance of a number from zero on the number line, always nonnegative, written |x|.
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What it means
|x| = a has two solutions, x = a and x = −a, when a > 0. |x − c| < d describes values within d of c, and |x − c| > d describes values more than d away from c.
Graphs of absolute value functions form a V shape with a vertex.
Example
|x − 5| = 3 gives x = 8 or x = 2. |x − 5| < 3 gives 2 < x < 8.
On the exam
Absolute value equations and inequalities appear on both tests, often to describe tolerances or distances.