2x²+1+4x²-2x-5=0
6(x²-x/3-2/3)=0
x²-x/3-2/3=0
(x-1/6)^2-1/36-2/3=0
(x-1/6)^2=25/36
x-1/6=±5/6
x=1/6±5/6=1 或者 -2/3