The cubic polynomial 8x3+kx2+14x−158x^3+kx^2+14x-158x3+kx2+14x−15 is denoted by f(x)f(x)f(x). It is given that (2x+3)(2x+3)(2x+3) is a factor of f(x)f(x)f(x).
Use the factor theorem to show that k=28k = 28k=28 and hence factorise f(x)f(x)f(x) completely.
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.