3x^3-√2x^2+3√2x^2-2x-(15-9√2)x-6+5√2=0
x^2(3x-√2)+√2x(3x-√2)+(3√2-5)(3x-√2)=0
(3x-√2)(x^2+√2x+3√2-5)=0
3x-√2=0得x=√2/3
x^2+√2x+3√2-5=0,得：x=[-√2±√(22-12√2)]/2