Free Absolute Value Inequalities Calculator

|ax b| < c

Enter values to see the solution

What Is an Absolute Value Inequality?

An absolute value inequality involves an expression such as |ax + b| related by <, ≤, >, or ≥ to a constant. Geometrically it describes the distance of ax + b from zero on the number line. This absolute value inequalities solver walks you through each stage of the solution, from isolating the absolute value to splitting the condition into two cases. Because the tool also outputs the result in compact interval form, it serves both as an inequality solver with steps and as an interval notation calculator.

With the coefficients a, b, and c entered for |ax + b| ⋈ c, the calculator instantly decides which rule to apply and displays the transformed inequality. Whether you are dealing with strict inequalities (<, >) or non‑strict ones (≤, ≥), the online solver keeps the steps clear and the algebra correct.

How the Solver Works

The logic behind solving |ax + b| ⋈ c depends on the comparison symbol:

For < or ≤ (conjunction)

If the inequality is |ax + b| < c and c > 0, then

−c<ax+b<c-c < ax + b < c

If |ax + b| ≤ c, the “<” is simply replaced by “≤”. The calculator then isolates x by performing the same operation on all three parts.

For > or ≥ (disjunction)

If |ax + b| > c and c ≥ 0, then

ax+b<−corax+b>cax + b < -c \quad \text{or} \quad ax + b > c

Similarly, |ax + b| ≥ c leads to “≤” and “≥”. Each branch is solved separately, and the union forms the final answer.

The solver also handles special cases:

  • When c is negative, |ax + b| < c has no solution while |ax + b| > c is true for all real x.
  • When c is zero, the inequality reduces to a simple equality check (e.g., |ax + b| < 0 is impossible).

Step‑by‑Step Example

Suppose you want to solve |2x – 3| ≤ 5. The |ax+b| inequality calculator shows:

  1. Because the symbol is “≤”, it applies the conjunction rule: –5 ≤ 2x – 3 ≤ 5.
  2. Add 3 to all parts: –2 ≤ 2x ≤ 8.
  3. Divide by 2: –1 ≤ x ≤ 4.

The solution in interval notation is [–1, 4]. Every arithmetic step is listed, making this truly a solve absolute value inequalities tool that builds understanding.

Why Use an Online Inequality Solver with Steps?

Manual solving can lead to sign errors, especially when splitting an inequality that involves a negative coefficient or a fraction. An absolute value inequality solver online automates the process while displaying each transformation. It also doubles as an interval notation calculator because it converts the final inequality into brackets and parentheses automatically. Students can verify their homework step by step, and teachers can use it to generate quick examples.

Key Formulas

For the standard form |ax + b| ⋈ c:

  • If ⋈ is < or ≤:
∣ax+b∣≤c  ⟺  −c≤ax+b≤c(provided c≥0)|ax + b| \leq c \iff -c \leq ax + b \leq c \quad (\text{provided } c \geq 0)
  • If ⋈ is > or ≥:
∣ax+b∣≥c  ⟺  ax+b≤−corax+b≥c(provided c≥0)|ax + b| \geq c \iff ax + b \leq -c \quad \text{or} \quad ax + b \geq c \quad (\text{provided } c \geq 0)

These equivalences are the engine behind every calculation. By keeping them visible, the |ax+b| inequality calculator reinforces the mathematical concept while delivering fast, reliable answers.

FAQ

1. How do I solve |ax + b| < c with this calculator?

Enter the coefficients a, b, and the constant c. The calculator applies the conjunction rule: –c < ax + b < c, then solves for x. It shows each step and gives the final inequality and interval notation.

2. Can the tool handle cases where c is negative?

Yes. For |ax + b| < c with c < 0, the solver correctly outputs “no solution”. For |ax + b| > c with c < 0, it outputs “all real numbers”.”

3. Does the solver also work for |ax + b| ≥ c ?

Absolutely. It treats ≥ and > similarly using the disjunction rule, splitting into two separate inequalities and returning the union of the solution sets.

4. What is interval notation and how does the calculator produce it?

Interval notation is a compact way to write solution sets using brackets [ ] for ≤ or ≥ and parentheses ( ) for < or >. The calculator converts the final compound inequality into an interval automatically.

5. Is the solution shown step by step?

Yes. The online solver lists every operation: applying the absolute value rule, adding/subtracting constants, multiplying/dividing by coefficients, and finally writing the answer in both inequality and interval form.

How to Use

  1. Enter the coefficient a of the x term inside the absolute value (e.g., 2 for |2x - 3|).
  2. Enter the constant b and select the inequality operator (<, ≤, >, ≥) and enter the right-hand side value c.
  3. View the solution instantly in both inequality notation and interval notation.