2026 IGCSE Additional Mathematics May/June 0606/22 Q6

In this question, \(a\), \(b\) and \(c\) are integers.

When the expansion of \((a+x)^4(1+ax)^5\) is written in ascending powers of \(x\), the first three terms are \(16+bx+cx^2\).

Find all the possible values of \(a\), \(b\) and \(c\).[8]