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 AQA GCSE Maths Proof with exam-style questions for Foundation and Higher tier. 56 questions, matched to the AQA GCSE Maths (8300) specification and written in Paper 1, Paper 2 and Paper 3 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.