(a)[2]
Determine the first three terms, in ascending powers of $x$, of the expansion of $(1 + 2x)^5$.
(b)[2]
Determine the first three terms, in ascending powers of $x$, of the expansion of $(1 - 3x)^4$.
(c)[2]
Hence determine the coefficient of $x^2$ in the expansion of $(1 + 2x)^5(1 - 3x)^4$.