Prove that (kn+3)2−(kn−3)2(kn + 3)^2 - (kn - 3)^2(kn+3)2−(kn−3)2 is a multiple of 6k 6k\,6k for all integer values of nnn, where k k\,k is a positive integer
257 exam-style questions on Edexcel A Level Maths Algebraic Methods, covering 7.1 Algebraic Fractions, 7.2 Dividing Polynomials, 7.3 The Factor Theorem, 7.4 Mathematical Proof, and 7.5 Methods of Proof. Each one has a worked solution and a mark scheme showing where the marks go.