The equation kx2+6kx+a=0kx^2 + 6kx + a = 0kx2+6kx+a=0, where k k\,k is a non-zero constant and a a\,a is a positive constant, has no real roots if and only if 0<k<49\displaystyle 0<k<\frac{4}{9}0<k<94.
Find the value of aaa.
322 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.