配方:
x^2+(√2+1)x+√2=0,
x^2+(√2+1)x+[(√2+1)/2]^2+√2-[(√2+1)/2]^2=0,
[x+(√2+1)/2]^2+√2-(3+2√2)/4=0,
[x+(√2+1)/2]^2+(3-2√2)/4=0