Teacher copy: This page may include teaching prompts or answer keys. Answer keys in this public library can be viewed by anyone. Give learners a clean prompt, use checks as formative evidence, and change a case locally when prior access matters.
Codes:AC9M8A01, AC9M8A03. Goal: independently expand, simplify, factorise and invert a new fictional model. Prepare: release only the Day15 section of learner checks; hold the staff key.
Launch · 2 min. Say this is a new situation and an internal formative check. Neutral reading and accessible notation are allowed.
Prior example · 5 min. Revisit different 3(x+4)=3x+12 and the x=2 check. Put it away before new numbers appear.
Instructions · 3 min. Ask learners to show every transformation and substitute back. Do not expand or factor the new expression for them.
Fresh check · 10 min. Give new-case Items 1–2. Save the first response; content prompts are noted separately.
Transfer exit · 3 min. Give Item 3, asking for a bounded interpretation. Later D15 choices use different values.
Note · 2 min. Separate distributive reasoning, collecting terms, inverse step and contextual limit. If access prevented response, mark not observed rather than wrong.
Later: Use D15 practice choices only after the check is secure.