1)x(x+8)(x-17)≤0
x=0 x=-8 x=17
_ + _ +
----------[-8]--------------[0]-------------------[17]--------------------
x∈(-∞;-8] U [0;17]
2)(X+3)(x-8)(x-20)>0
x=-3 x=8 x=20
_ + _ +
---------(-3)--------------(8)-------------------(20)--------------------
x∈(-3;8) U (20;∞)
3)-x(x-1)(5-x)(x+20)>0
x(x-1)(x-5)(x+20)>0
x=0 x=1 x=5 x=-20
+ _ + _ +
-------------(-20)-----------(0)----------------(1)-----------------(5)------------------
x∈(-∞;-20) U (0;1) U (5;∞)