问题
解答题
解方程:
(1)2x2-5=4x
(2)x2-4x+1=0.
答案
(1)2x2-5=4x,
移项得:2x2-4x-5=0,
x=
,4± 16+40 4
∴x1=
,x2=2+ 14 2
;2- 14 2
(2)x2-4x+1=0,
x2-4x=-1,
x2-4x+4=3,
(x-2)2=3,
x-2=±
,3
x1=2+
,x2=2-3
;3
解方程:
(1)2x2-5=4x
(2)x2-4x+1=0.
(1)2x2-5=4x,
移项得:2x2-4x-5=0,
x=
,4± 16+40 4
∴x1=
,x2=2+ 14 2
;2- 14 2
(2)x2-4x+1=0,
x2-4x=-1,
x2-4x+4=3,
(x-2)2=3,
x-2=±
,3
x1=2+
,x2=2-3
;3