P1.1.5 - Completing the square

Completing the square and solving quadratic equations.; Solve quadratic equations by factorisation, formula, calculator methods and completing the square.

Use completing the square to connect the rule to the data and decision in the question.

This matters because completing the square determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply completing the square to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: Completing the square is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.