1) (x-1)(x-4)>0
x=1 x=4
+ - +
-------- 1 --------- 4 ----------
\\\\\\\\ \\\\\\\\\\\
x∈(-∞; 1)∨(4; +∞)
2) х-2 <0<br> x+3
{x+3≠0
{(x-2)(x+3)<0<br>
x≠-3
(x-2)(x+3)<0<br>x=2 x=-3
+ - +
-------- -3 ---------- 2 -------------
\\\\\\\\\\\
x∈(-3; 2)
3) х²+7х+3≤0
х²+7х+3=0
Д=49-4*3=37
х₁=-7-√37
2
х₂=-7+√37
2
+ - +
---------- -7-√37 ------------ -7+√37 --------------
2 \\\\\\\\\\ 2
х∈(-7-√37; -7+√37)
2 2