Inequality to Interval Notation Calculator

Solve a linear inequality ax + b ≷ c and write the interval.

Operator

x boundary 4

Interval (-∞, 4)

Formula: Isolate x; flip the sign if dividing by a negative

Step-by-step with your numbers:

1. Values used:

2. a = 2

3. b = 1

4. c = 9

6. x boundary = 4

7. Interval = (-∞, 4)

Did we solve your problem today?

Solve a one-variable linear inequality and express the solution set in interval notation.

The math behind it

Isolate x just like an equation, but remember to flip the inequality sign whenever you multiply or divide by a negative number.

2x + 1 < 9 → x < 4 → (−∞, 4).

When does the sign flip?

Only when you multiply or divide both sides by a negative value.