How is the inequality x greater than 3 written in interval notation?
- The interval (3, infinity)
- The interval [3, infinity)
- The interval (infinity, 3)
- The interval (0, 3)
Show answer and solution
Correct answer: A. The interval (3, infinity)
1. Every number to the right of 3 satisfies the inequality, but 3 itself does not.
2. An excluded endpoint is written with a parenthesis rather than a bracket.
3. There is no upper end, so infinity closes the interval, giving (3, infinity).
_Source: OpenStax Intermediate Algebra (CC BY 4.0), Ch 2 "Solving Linear Equations", section 2.5 Solve Linear Inequalities_