Решите неравенство:(x-1)(4-x)(x+5)0

(x-1)(4-x)(x+5)0
=============
(x-1)*(4-x)0
x+50

 (x-1)*(4-x)0
x+50
=============
x-10
 4-x0
x-10
4-x0

x+5-50-5


x-10
4-x0
x-10
4-x0

x+5-50-5

================
x1
x4
x1
x4

x-5

x1
x4
x1
x4

x-5

==============

Отсюда 

x[1,4]
x
x-5

 x(-,1]
x[4,+)
x-5
================
x[1,4]
x-5

 x(-,1][4,+)
x-5

============

x[1,4]
x(-,-5]

Ответ: x(-,-5][1,4]

(х-1)(4-х)(х+5)  0
х-1=0,  х = 1
4-х = 0,  х = 4
х+5 = 0, х = -5
  
    +         -            +           -
-------.----------.-----------.---------gt; x
       -5           1            4
x(-; -5][1; 4]