The cubic polynomial 6x3+kx2+x−26x^3 + kx^2 + x - 26x3+kx2+x−2 is denoted by f(x)f(x)f(x). It is given that (2x+1)(2x + 1)(2x+1) is a factor of f(x)f(x)f(x).
Use the factor theorem to show that k=13k = 13k=13.
Using this value of kkk, 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.