Prove that (3n+1)2−(3n−1)2(3n + 1)^2 - (3n - 1)^2(3n+1)2−(3n−1)2 is always a multiple of 12, for all positive integer values of nnn.
Practise CIE IGCSE Maths Proof with exam-style questions for Core and Extended tier. 14 questions, matched to the CIE IGCSE Maths (0580) specification and written in Paper 1 and Paper 3 (Core) or Paper 2 and Paper 4 (Extended) style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.