tolong di bantu kawan

a. -11<=9-2x<=11
-20<=-2x<=2
-10<=-x<=1
-1<=x<=10
b. |2x-1|>=|x+2|
(2x-1)^2>=(x+2)^2
(2x-1)^2 - (x+2)^2 >= 0
[(2x-1)-(x+2)]*[(2x-1)+(x+2)] >= 0
(x-3)(3x+1)>=0
x<=-1/3 atau x>=3

c. |2x+1|<|2x-3|
(2x+1)^2 < (2x-3)^2
4x^2 + 4x +1 <4x^2-12x+9
16x<8
x<2