Prove that, for all values of xxx,
x2+6x+20>x+4 x^2 + 6x + 20 > x + 4 x2+6x+20>x+4211 exam-style questions on Edexcel A Level Maths Quadratics, covering 2.1 Solving Quadratics, 2.2 Completing the Square, 2.3 Sketching Quadratic Graphs, 2.4 The Discriminant, and 2.5 Modelling with Quadratics. Each one has a worked solution and a mark scheme showing where the marks go.