Solve a linear inequality
A standard method from Linear inequalities in one unknown: the steps and worked examples.
Steps
- Solve exactly like an equation: expand, move terms, collect.
- If you multiply or divide by a negative number, flip the sign.
- Draw the number line: hollow circle for > or <, solid dot for ≥ or ≤.
- For "greatest integer" or "least integer", read it off the number line.
Why the flip: 3 > 2, but −3 < −2. Multiplying by −1 swaps the order of numbers on the number line.
Safer habit: move the x-terms to the side where the coefficient stays positive, so you never divide by a negative.
Worked examples
Example 1: Solve the linear inequality 3 − 2x > 7.
−2x > 4
x < −2 divide by −2, flipFor the whole topic, read Linear inequalities in one unknown: key points, common mistakes and how the DSE tests it.