易错点1:忽视用字母表示的两个数的大小例1若a<0,则关于x的不等式x~2-4ax-5a~2>0的解集是_____.错解x<-a或x>5a分析错解中解集的形式不对,同时也没搞清5a与-a的大小关系.正解{x|x<5a或x>-a}易错点2:忽视不等式中定值的条件 Error-prone points 1: Neglecting the size of two numbers in alphabetic example 1 If a <0 then the solution set for the inequality x ~ 2-4ax-5a ~ 2> 0 for x is _____. a or x> 5a analysis of the wrong solution set in the wrong form, but also did not find out the size of the relationship between 5a and -a positive solution {x | x <5a or x> -a} easy to wrong 2: ignoring the inequality set Conditions of value