Exam-style question
Try this first
After solving a quadratic formed in a function of x, what final check is essential?.
- A.B3: connect the result back to the original question
- B.Use any familiar GCSE calculation even if it ignores quadratic functions and their graphs
- C.Write only the final answer without showing the mathematical method
- D.Change the notation or restrictions to make the algebra look simpler
Model answer
What a good answer should say
- The correct answer is B3: connect the result back to the original question.
- Solutions found for a substituted expression must be converted back to the original variable and checked against any restrictions introduced during the substitution.
This answer is tied to the objective: B3 Work with quadratic functions and their graphs; use the discriminant including the conditions for real and repeated roots; complete the square; solve quadratic equations including solving quadratic equations in a function of the unknown..
Explanation
Why this works
Use the explanation to connect the worked answer back to B3 Work with quadratic functions and their graphs; use the discriminant including the conditions for real and repeated roots; complete the square; solve quadratic equations including solving quadratic equations in a function of the unknown..
The correct option, B3: connect the result back to the original question, is supported because solving a quadratic in a function of the unknown can produce values for the substituted expression rather than the original variable. A full answer must return to the original question and reject any invalid values.
Maths method check
- Topic focus: Pure Mathematics.
- Question style: practice.
- Reasoning demand: analysis.
- Check the operation, notation, units, and final answer form against the question before moving on.
Common mistake
No common mistake is linked to this question yet.