x^2-2x+1=9x^2+6x+1
(x-1)^2=(3x+1)^2
(x-1)^2-(3x+1)^2=0
[(x-1)-(3x+1)][(x-1)+(3x+1)]=0
(-2x-2)*4x=0
x(x+1)=0
x=0或x=-1