MATHS help

設f(x)=3x3-2x-9。
餘式=f(1/2)
=3(1/2)3-2(1/2)-9
=3/8-1-9
=- 77/8

3x^3-2x-9除不盡(2x-1)的.

By remainder theorem, 3x^3-2x-9=(2x-1)Q(x)+R
put x=1/2,
if 3x^3-2x-9除得盡(2x-1), R應該等於0

but
3(1/2)^3-2(1/2)-9=[2(1/2)-1]Q(X) +R
8/3-10=0+R
R=-77/3

R does not equal to 0,
so 3x^3-2x-9除不盡(2x-1)的