(x+1)(2x-8)(3x+6)≤0
(x+1)*2(x-4)*3(x+2)≤0
(x+1)(x-4)(x+2)≤0
x=-1 x=4 x= -2
- + - +
------------- -2 ------------- -1 -------------- 4 -------------
\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\
x∈(-∞; -2) x= -3 - - - | -
x∈(-2; -1) x= -1.5 - - + | +
x∈(-1; 4) x=0 + - + | -
x∈(4; +∞) x=5 + + + | +
x∈(-∞; -2]U[-1; 4].