x^2-2x-5=0化成（x+a)^2=b的形式为_（x-1)^2=6_______,所以方程的根为_x=1-+√6
x^2-2x-5=0x^2-2x+1-6=0(x-1)^2=6x-1=±√6x=1±√6
x^2-2x-5=0,x^2-2x=5,x^2-2x+1=6(x-1)^2=6,x-1=√6,x-1=-√6x=1+√6,x2=1-√6
(x-1)^2=6x=1±√6
