1、4x²=81
x²=81/4
x=9/2 x=-9/2
2、5(x-2)²-245=0
(x-2)²=49
x-2=7 x-2=-7
x=9 x=-5
3、(x-1)³+27=0
(x-1)³=-27
x-1=-3
x=-2 4、(-根号3)²-根号(-4)²--(-8的立方根)-|1-根号2|=3-4-(-2)-(√ 2-1)=2-√2
1、4x²=81
x²=81/4
x=9/2 x=-9/2
2、5(x-2)²-245=0
(x-2)²=49
x-2=7 x-2=-7
x=9 x=-5
3、(x-1)³+27=0
(x-1)³=-27
x-1=-3
x=-2 4、(-根号3)²-根号(-4)²--(-8的立方根)-|1-根号2|=3-4-(-2)-(√ 2-1)=2-√2