2) ¹/₃ х ≤0
х²-8
{x²-8≠0
{¹/₃ x (x²-8)≤0
x²-8≠0
(x-√8)(x+√8)≠0
x-√8≠0 x+√8≠0
x≠√8 x≠-√8
¹/₃ x(x²-8)≤0
x(x²-8)≤0
x(x-√8)(x+√8)≤0
x=0 x=√8 x=-√8
- + - +
--------- -√8 ------------ 0 ------------- √8 ----------------
\\\\\\\\\\ \\\\\\\\\\\\\
x∈(-∞; -√8)∨[0; √8)
4) 5-х <0<br> 2-18x²
{2-18x²≠0
{(5-x)(2-18x²)<0<br>
2-18x²≠0
2(1-9x²)≠0
1-9x²≠0
(1-3x)(1+3x)≠0
1-3x≠0 1+3x≠0
-3x≠-1 3x≠-1
x≠1/3 x=-1/3
(5-x)(2-18x²)<0<br>-(x-5)(2-18x²)<0<br>2(1-9x²)(x-5)>0
-(9x²-1)(x-5)>0
(3x-1)(3x+1)(x-5)<0<br>x=1/3 x=-1/3 x=5
- + - +
--------- - 1/3 ----------- 1/3 --------- 5 ---------
\\\\\\\\\\ \\\\\\\\\\
x∈(-∞; -1/3)∨(1/3; +∞)