The equation
\((x-1)(x-2)(x-4)(x-5)(x-7)(x-8)=(x-3)(x-6)(x-9)\)
has distinct roots \(r_1,r_2,...,r_6\). Evaluate
\(\displaystyle\sum_{i=1}^{6}(r_i-1)(r_i-2)(r_i-4)\)
I couldn't see a neat way of doing this analytically, so I used a numerical approach: