0606 P11 - Nov 2022 - Q6 - 7 marks
7852
The first three terms, in ascending powers of \(x\), in the expansion of
\(\left(1-\frac{2x}{9}\right)^{18}(1+3x)^3\)
are written in the form
\(1+ax+bx^2,\)
where \(a\) and \(b\) are constants. Find the exact values of \(a\) and \(b\).
