By completing the square, find in terms of the constant k k\,k the roots of the equation
x2+2kx−6=0 x^2 + 2kx - 6 = 0 x2+2kx−6=0Hence find the exact roots of the equation x2+4x−6=0x^2 + 4x - 6 = 0x2+4x−6=0
211 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.