1
(6-x)/(x-3)-2>0
(6-x-2x+6)/(x-3)>0
(12-6x)/(x-3)>0
x=2 x=3
_ + _
-------------------(2)--------------------(3)---------------
x∈(2;3)
2
(x-1)(2-x)(3-x)(3+x)≥0
x=1 x=2 x=3 x=-3
+ _ + _ +
---------------[-3]------------[1]---------[2]------------[3]-------------
x∈ (-∞;-3] U [1;2] U [3;∞)
3
15/(4+3x-x²-1>0
(15-4-3x+x²)/(x²-3x-4)<0<br> (x²-3x+11)/[(x-4)(x+1)]<0<br>x²-3x+11>0 при любом х,т.кD<0⇒(x-4)(x+1)<0<br> x=4 x=-1
+ _ +
--------------(-1)-------------(4)--------------
x∈(-1;4)