解一元二次不等式3x^2-2x-1≥0

3x^2-2x-1=0
x^2-2/3x-1/3=0
x^2-2/3x=1/3
x^2-2/3+1/9=1/3+1/9
(x-1/3)^2=4/9
所以x1=1 x2=-1/3 又因为a=3>0
所以3x^2-2x-1≥0 的解集为 X小于等于-1/3或X大于等于1
(1)2x^2+2x-1<0
x^2+x-1/2<0
(x-1)(x+1/2)<0
-1/2<x<1
(2)3-x^2≥0
3≥x^2
根号3≥X≥-根号3

3x^2-2x-1≥0
(x-1)(3x+1)≥0
→x≤-1/3或x≥1

（3x+1)(x-1）≥0
x≥1或x≤-1/3