Question

解关于x的不等式ax²-(a+1)x+1<0

Answer 1

ax^2-(a+1)+1<0
ax^2-ax-x+1<0
(x-1)(ax-1)<0

1)当a<0
(x-1)(x-1/a)a<0
(x-1)(x-1/a)>0
x<1/a或 x>1.

2)当a=0
-(x-1)<0
x>1

3)当0<a<1,
1/a>1
(x-1)(x-1/a)<0
x<1或 x>1/a.

4)当a=1
(x-1)^2<0
x∈Φ.

5)当a>1
0<1/a<1
(x-1)(x-1/a)<0
1/a<x<1.

当0<a<1时，要先将式子同除以a?
回答:因为要先证明x-1是大于零还是小于零,把第二个括号里面的
ax-1变成a(x-1/a),

Answer 2

帮顶，拿分!