k k\,k is an integer. Prove algebraically that the sum of k(k−5)k(k - 5)k(k−5) and k+4k + 4k+4 is always a square number.
Practise Edexcel GCSE Maths Proof with exam-style questions for Foundation and Higher tier. 56 questions, matched to the Edexcel GCSE Maths (1MA1) 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.