Algebra 1 Intermediate

Absolute Value Inequalities

Solve |ax + b| < c (AND case → bounded interval) and |ax + b| > c (OR case → unbounded rays) with step-by-step work and number line visualization. Handles all special cases including no solution and all real numbers.

Live Calculator · Step-by-Step · Algebra 1
Input
Enter |ax + b| ◇ c
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a
x
+ b
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c
|x − 2| < 5
Examples
Solution
Enter values and click Solve to see the solution.
Step-by-Step Solution
Number Line
Absolute Value Inequalities — The Two Cases
|expr| < c  →  −c < expr < c  (AND, bounded) |expr| > c  →  expr < −c  OR  expr > c  (OR, unbounded)

Less than (< or ≤): |ax + b| < c means ax + b is within c units of 0 — it produces a three-part AND inequality: −c < ax + b < c. Solve all three parts simultaneously. Result: a bounded interval between two values.

Greater than (> or ≥): |ax + b| > c means ax + b is more than c units from 0 — it splits into two separate inequalities: ax + b < −c OR ax + b > c. Solve each branch. Result: two unbounded rays extending to ±∞.

Remember: when dividing by a negative coefficient, flip the inequality sign(s).

Think of |expr| < c as "distance from zero is less than c" — the expression is trapped between −c and c.
Special Cases
|expr| < 0 → No Solution  |  |expr| > −1 → All Reals

c < 0, less-than type: |expr| < c is impossible — absolute value is always ≥ 0, so it can never be less than a negative number. Answer: No Solution (∅).

c < 0, greater-than type: |expr| > c is always true — any absolute value is greater than every negative number. Answer: All Real Numbers (−∞, +∞).

c = 0, less-than strict: |expr| < 0 is impossible. Answer: No Solution.

c = 0, less-than-or-equal: |expr| ≤ 0 forces expr = 0, giving exactly one point x = −b/a.

c = 0, greater-than strict: |expr| > 0 means expr ≠ 0, so x ≠ −b/a — all reals except one point.

c = 0, greater-than-or-equal: |expr| ≥ 0 is always true. Answer: All Real Numbers.

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