2x^2-2√2x-2
=2（x²-√2x-1)
=2[x²-√2x+(√2/2)²-1-(√2/2)²]
=2[(x-√2/2)²-3/2]
=2[(x-√2/2)+√3/2][(x-√2/2)-√3/2]
=2[x-(√2-√3)/2][x-(√2+√3)/2]
2x^2-2√2x-2
=2（x²-√2x-1)
=2[x²-√2x+(√2/2)²-1-(√2/2)²]
=2[(x-√2/2)²-3/2]
=2[(x-√2/2)+√3/2][(x-√2/2)-√3/2]
=2[x-(√2-√3)/2][x-(√2+√3)/2]