Assume that xxx and yyy are integers such that
x2−8y−6=0 x^2 - 8y - 6 = 0 x2−8y−6=0Prove that xxx is even.
Hence, prove that 4y+34y + 34y+3 is even and explain why this leads to a contradiction.
Explain what can be deduced about the integer solutions to the equation x2−8y−6=0x^2 - 8y - 6 = 0x2−8y−6=0.
107 exam-style questions on OCR A Level Maths 1.1 Proof, covering 1.1.1 Structure of mathematical proof, 1.1.2 Logical connectives, 1.1.3 Disproof by counter example, 1.1.4 Proof by contradiction (A-level only), and 1.1 Proof. Each one has a worked solution and a mark scheme showing where the marks go.