2x^2-4x-8=0怎么解啊
问题描述：
2x^2-4x-8=0怎么解啊
答
2x^2-4x-8=0
x^2-2x-4=0
(x-1)^2=4+1
x-1=±√5
x=1±√5
答
即x²-2x=4
x²-2x+1=4+1
(x-1)²=5
x-1=±√5
x=1-√5,x=1+√5