数学题目不懂，请教下，感激不尽

1、x<0显然在解集内，x>0时，2x>3，x>3/2

综上{x|x<0或x>3/2}

2、x²-2x+1≤0，解集{x|x=1}

3、(3x+1)(x-2)≥0，解集{x|x≥2或x≤-1/3}

4、(x-4)(x+3)≤0，非负整数集{0,1,2,3,4}

1.2x^2>3x
2x^2-3x>0
x(2x-3)>0
x>3/2或x<0
2.2x-1≥x^2
x^2-2x+1≤0
(x-1)^2≤0
x=1
3.(3x+1)(2-x)≤0
(3x+1)(x-2)≥0
x≥2或x≤-1/3
4.x^2-x-12≤0
(x-4)(x+3)≤0
-3≤x≤4
x=0,1,2,3,4

1.2x^2-3x>0
x(2x-3)>0
x>3/2或x<0
2.2x-1>=x^2
x^2-2x+1<=0
(x-1)^2<=0
则x=1
3.(3x+1)(2-x)<=0
则x>=2或x<-1/3
4.x^2-x-12<=0
(x-4)(x+3)<=0
则
-3<=x<=4