Key Idea: Absolute Value

Absolute value represents a number’s distance from zero, which is always non-negative.
When solving equations or simplifying expressions, once you get the absolute value by itself, you split into two cases — one positive and one negative.

General Rule:

If

∣expression∣=a

then

expression=a or expression=−a

Why this matters for the SAT:

Absolute value equations often appear disguised in algebra problems. Recognizing when the absolute value is isolated and correctly setting up two separate cases is key to finding all valid solutions.