原式=-[(x-3)/(x-2)]÷{[(x+2)(x-2)-5]/(x-2)]
=-[(x-3)/(x-2)]÷[(x²-9)/(x-2)]
=-(x-3)/(x+3)(x-3)
=-1/(x+3)
=-1/(3+2√2)
=-(3-2√2)/(9-8)
=2√2-3