【1】
(x²-2x-3)(x+4)≤0
(x-3)(x+1)(x+4)≤0
则:
x≤-4或-1≤x≤3
解集是:{x|x≤-4或-1≤x≤3}
【2】
x²-4x+4≤0
(x-2)²≤0
x=2
解集是:{2}
【3】
(x+2)/(2x+1)<0
-2
【4】
(6-x)/(x+3)≥1
1+(x-6)/(x+3)≤0
(2x-3)/(x+3)≤0
-3
【5】
|4x-1|≥2
4x-1≤-2或4x-1≥2
x≤-1/4或x≥3/4
解集是:{x|x≤-1/4或x≥3/4}
【6】
|4x+3|<1
-1<4x+3<1
-4<4x<-2
-1
1.(x-3)(x+1)(x+4)<=0
x1=3,x2=-1,x3=-4
x<=-4,-1<=x<=3
2.x^2-4x+4<=0
(x-2)^2<=0
(x-2)^2>=0
(x-2)^2=0
x=2
3.(x+2)/(2x+1)<0
(x+2)(2x+1)<0
x1=-2,x2=-1/2
-2
(6-x)/(x+3)-1>=0
(6-x-x-3)/(x+3)>=0
(3-2x)/(x+3)>=0
(2x-3)(x+3)<=0,且x/=-3
-3<=x<=3/2且x/=-3
-3
4x-1>=2or4x-1<=-2
4x>=3or4x<=-1
x>=3/4orx<=-1/4
6./4x+3/<1
-1<4x+3<1
-4<4x<-2
-1
1
(x-3)(x+1)(x-4)<=0
根据穿根法,三个根分别是-1,3,4,从右上方开始穿,小于零看轴的下方
就得到x<=-1,或3<=x<=4
2
(x-2)^2<=0
x=2
3
同理
两个根-1/2,-2,
-2
(6-x)/(x+3)-1>=0
(2x-3)/(x+3)<=0
大于在两边,小于在中间
分母不为零
所以-3
两边平方
(4x-1)^2>=4
(4x+1)(4x-3)>=0
-1/4<=x,x>=3/4
6
同上