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 OCR GCSE Maths Proof with exam-style questions for Foundation and Higher tier. 56 questions, matched to the OCR GCSE Maths (J560) specification and written in the written papers 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.