The cubic polynomial 6x3+kx2−19x+46x^3 + kx^2 - 19x + 46x3+kx2−19x+4 is denoted by f(x)f(x)f(x), where k k\,k is a constant.
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=19k = 19k=19.
Using this value of kkk, factorise f(x)f(x)f(x) completely.