y=(x²-8x+15)/(x²-x-6)=(x-3)(x-5)/(x-3)(x+2)=(x-5)/(x+2)(x≠3)

　　=1-7/(x+2)(x≠3)

　　∴y≠1且y≠(3-5)/(3+2)=﹣2／5

　　∴值域是﹛y|y∈R且y≠1且y≠﹣2／5﹜