Variation 1 · answer guide
Absolute value inequality — A bounded interval
Question
Solve .
This practice question was inspired by Question 1 in the 2025 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.
Step by step
- Set up the solution: separate the absolute-value statement into its valid algebraic cases.
- Simplify the previous line carefully, keeping exact values where possible.
- Finish the calculation, then check that the result meets the question’s conditions.
- Match the result to the choices and state the correct option.Therefore option A is correct:
Common mistake: changing so many features that the new example no longer tests the same mathematical idea.
Verification: Test (inside) and (outside) in the original inequality.
Any mark labels are a TestMum study aid, not an official NESA marking allocation.
← Back to 2025 HSC Extension 1 paper Question 1