a a\,a is an integer. Prove algebraically that the sum of a(a+7)a(a + 7)a(a+7) and a+16a + 16a+16 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.