Expand (k+6x)−12\displaystyle (k+6x)^{-\frac{1}{2}}(k+6x)−21 in ascending powers of x x\,x up to and including x3x^3x3, where k k\,k is a positive constant, giving your answer in terms of kkk.
Write down the range of values of x x\,x in terms of k k\,k for which the expansion is valid.
408 exam-style questions on Edexcel A Level Maths Binomial Expansion, covering 4.1 Expanding (1 + x)^n, 4.2 Expanding (a + bx)^n, and 4.3 Using Partial Fractions. Each one has a worked solution and a mark scheme showing where the marks go.