(a(i))[1]
Expand $(1 + 2x)^5$ in powers of $x$ from lowest to highest, including terms up to and including $x^2$.
(a(ii))[2]
Expand $(1 - ax)^6$, where $a$ is a constant, in increasing powers of $x$ up to and including the $x^2$ term.
(b)[4]
In the expansion of $(1 + 2x)^5(1 - ax)^6$, the coefficient of $x^2$ is $-5$. Determine the possible values of $a$.