题目: 计算:(1)(2a+3b+1)(1-2a-3b)+(2a-3b)2(2)xx-1÷x2-xx2-1+11-x. 答案: (1)原式=1-(2a+3b)2+(2a+3b)2=1;(2)原式=xx-1•(x+1)(x-1)x(x-1)+11-x=x+1x-1-1x-1=xx-1.