(x²-3x)/(x²-5x) * (2x-10)/(x²-6x+9) 题目多打了一个y
=(x-3)/(x-5) * 2(x-5)/(x-3)²
=2/(x-3)
=2/(5-3)
=1先化简，再求值(x²-3x)/(x²-5x) * (2x-10)/(x²-6x+9) 题目多打了一个y=(x-3)/(x-5) * 2(x-5)/(x-3)²=2/(x-3)当x=5原式=2/(5-3)=1可是....当x=5,分母x²-5x=0,题目无意义的.反正题解出来...就好