9*(a - 1)*(a + 2)
9*(a - 1*1)*(a + 2)
9*(-1 + a)*(2 + a)
1*(a + 2)*(a - 1)
(1*(a + 2))*(a - 1)
2 -18 + 9*a + 9*a
-18 + 9*a + 9*a^2
9.0*(2.0 + a)*(-1.0 + a)