5. 다항함수 f(x)f(x)f(x)가 f′(x)=x(3x+2), f(1)=6f\prime(x)=x(3x+2),\ f(1)=6f′(x)=x(3x+2), f(1)=6을 만족시킬 때, f(0)f(0)f(0)의 값은? [3점]