a²(x-1)＜3a+x+2两边同时加上 a²+a²(x-1)＜3a+x+2+a²化解,得：a²（1+x-1)＜(a+1)(a+2)+x移项,得：a²x-x＜(a+1)(a+2)公式变形,得：（a²-1）x = (a+1）(a-1)所以,(a+1）(a-1)x＜(a...