(i)[5]
Use the factor theorem to determine the value of $a$ and hence factorise $f(x)$ completely.
(ii)[4]
Hence, without using a calculator, solve the equation $f(2x) = 3f(x)$.
Mathematics 9709 · AS & A Level · Algebra
Algebra — practice question
The cubic polynomial $f(x)$ is written as $f(x) = x^3 + ax^2 + 14x + a + 1$, with $a$ as a constant. It is stated that $(x + 2)$ is a factor of $f(x)$.