x平方-x-2/x平方-x-6除以x平方+4x-5/x平方+3x-10=[(x-2)(x+1)/(x-3)(x+2)]/[(x+5)(x-1)/(x+5)(x-2)]=[(x-2)(x+1)/(x-3)(x+2)]×[(x+5)(x-2)/(x+5)(x-1)]=(x-2)²(x+1)/(x-3)(x+2)(x-1)