(x^2-x-6)/(x-3)÷[(x-3)/(x^2-5x+6)]
=(x^2-x-6)/(x-3)(x^2-5x+6)/(x-3)
=(x+2)(x-3)(x-2)(x-3)/(x-3)^2
=(x-2)(x+2)
=x^2-4
x^2就是x²抱歉，能把乘号体现出来吗？(x²-x-6)/(x-3)÷[(x-3)/(x²-5x+6)]=(x²-x-6)/(x-3)×(x²-5x+6)/(x-3)=(x+2)×(x-3)×(x-2)×(x-3)/(x-3)²=(x-2)×(x+2)=x²-4