问题
解答题
用适当的方法解下列方程
(1)81x2-25=0.
(2)x2-4x+4=0.
答案
(1)81x2-25=0,
81x2=25,
x2=
,25 81
x=±
,5 9
x1=
,x2=-5 9
. 5 9
(2)x2-4x+4=0,
(x-2)2=0,
x-2=0,
x1=x2=2.
用适当的方法解下列方程
(1)81x2-25=0.
(2)x2-4x+4=0.
(1)81x2-25=0,
81x2=25,
x2=
,25 81
x=±
,5 9
x1=
,x2=-5 9
. 5 9
(2)x2-4x+4=0,
(x-2)2=0,
x-2=0,
x1=x2=2.