求满足下列各式的未知数x.(1) 3(x+1)²=27; (2) 3x³+81除以125=03(x-1)²=27
问题描述：
求满足下列各式的未知数x.(1) 3(x+1)²=27; (2) 3x³+81除以125=0
3(x-1)²=27
答
(1)
3(x+1)²=27
(x+1)²=9
x+1=±3
x=-4或x=2
(2)
3x³+81/125=0
3x³=-81/125
x³=-27/125
x=-3/5
(3)
3(x-1)²=27
(x-1)²=9
x-1=±3
x=-2或x=4
答
.(1) 3(x-1)²=27
(x-1)²=9
x-1=±3
x1=4,x2=-2
(2) 3x³+81除以125=0
3x³=-81/125
x³=-27/125=(-3/5)³
x=-3/5