x³=-1/27移项,得x³+1/27=0即x³+(1/3)³=0根据立方和公式,得(x+⅓)(x²-⅓x+1/9)=0∴x+⅓=0或x²-⅓x+1/9=0∵x²-⅓x+1/9=（x-1/6)²+1/12>0解得∴x=-&...