问题
解答题
解方程:(1)x2-3x+1=0
(2)3(x-5)2=x2-25.
答案
(1)∵△=(-3)2-4×1×1=5,
∴x=3± 5 2
∴x1=
,x2=3+ 5 2
;3- 5 2
(2)3(x-5)2-(x+5)(x-5)=0,
(x-5)[3(x-5)-(x+5)]=0,
(x-5)(3x-20)=0,
x-5=0,2x-20=0,
∴x1=5,x2=10.
解方程:(1)x2-3x+1=0
(2)3(x-5)2=x2-25.
(1)∵△=(-3)2-4×1×1=5,
∴x=3± 5 2
∴x1=
,x2=3+ 5 2
;3- 5 2
(2)3(x-5)2-(x+5)(x-5)=0,
(x-5)[3(x-5)-(x+5)]=0,
(x-5)(3x-20)=0,
x-5=0,2x-20=0,
∴x1=5,x2=10.