(1)9(2x-5) 2=4
(2x-5) 2=
4
9 ,
开方得:2x-5=±
2
3 ,
x 1=
17
6 ,x 2=
13
6 .
(2)x 2-4x+1=0,
x 2-4x=-1,
配方得:x 2-4x+4=-1+4,
(x-2) 2=3,
开方得:x-2= ±
3 ,
x 1=2+
3 ,x 2=2-
3 .
(1)9(2x-5) 2=4
(2x-5) 2=
4
9 ,
开方得:2x-5=±
2
3 ,
x 1=
17
6 ,x 2=
13
6 .
(2)x 2-4x+1=0,
x 2-4x=-1,
配方得:x 2-4x+4=-1+4,
(x-2) 2=3,
开方得:x-2= ±
3 ,
x 1=2+
3 ,x 2=2-
3 .