résoudre l'inéquation : svp

bonjour,
a)
-4/3x+2/3=0
4/3x=2/3
x=(2/3)÷(4/3)
x=(2/3)*(3/4)
x=(2*3)/(3*4)
x=2/4
x=1/2x=0.5
b)
2/3x+2=0
2/3x=-2
x=(-2)÷(2/3)
x=(-2)*(3/2)
x=(-2*3)/2
x=-3

x                             -∞                   -3                    0.5                  +∞
(-4/3x+2/3)                         +                  +             0               -
2/3x+2                                -           0      +                             +
(-4/3x+2/3)(2/3x+2)            -           0       +            0               -

(-4/3x+2/3)(2/3x+2)≤0
x ∈]-∞,-3]  ∪ [0.5;+∞[