①(x²-6x+6)/(x²-1)▪(x²+x)/(x-3)②（xy-x²）÷(x-y)/xy③[(x²-y²)/y]²÷(x²+xy)³▪[xy/(y-x)]²④[(x²+2x-3)/(9-x²)]³▪[-(x-3)/(1-x)]²

①(x²-6x+6)/(x²-1)▪(x²+x)/(x-3)
②（xy-x²）÷(x-y)/xy
③[(x²-y²)/y]²÷(x²+xy)³▪[xy/(y-x)]²
④[(x²+2x-3)/(9-x²)]³▪[-(x-3)/(1-x)]²

一看你就是那种不写作业的

你去菁优网吧

第一题题目肯定有问题