多項式函數問題

已知g(x)=(x+2)(x－1)(x－4)
請問g(x－2)+4 等於多少呢?
Sol
g(x－2)+4
=(x－2+2)(x－2－1)(x－2－4)+4
=x(x－3)(x－6)+4
=x^3－9x^2+18x+4

g(x - 2) + 4 = (x - 2 + 2)(x - 2 - 1)(x - 2 - 4) + 4
= x(x - 3)(x - 6) + 4
= (x ^ 2 - 3x)(x - 6) + 4
= x ^ 3 - 6x ^ 2 - 3x ^ 2 + 18x + 4
= x ^ 3 - 9x ^ 2 + 18x + 4