9(x-1)^2=(2x+1)^2
9(x-1)^2-(2x+1)^2＝0
[3(x-1)+(2x+1)][3(x-1)-(2x+1)]＝0
(5x-2)(x-4)=0
5x-2=0 x-4=0
x1=2/5 x2=4