f(x)=x(x²-27)=x³-27xf'(x)=3x²-27=3(x-3)(x+3)f'(x)=0时,x=-3或3当f'(x)≤0时,-3≤x≤3当f'(x)＞0时,x＜-3或x＞3∴f(x)在（-无穷,-3）和（3,+无穷）单调递增在（-3,3）单调递减所以f(x)在x=-3处取得...