1)
a)
(x+2)(x-4)>0
x= -2 x=4
+ - +
--------- -2 ------------- 4 --------------
\\\\\\\\\\\ \\\\\\\\\\\\\\\\\
x∈(-∞; -2)U(4; +∞)
б)
x(x-4)≤0
x=0 x=4
+ - +
---------- 0 ----------- 4 ------------
\\\\\\\\\\\\\
x∈[0; 4]
2)
a)
x²+2x-3≤0
x²+2x-3=0
D=2² -4*(-3)=4+12=16
x₁= (-2-4)/2= -3
x₂=(-2+4)/2=1
+ - +
---------- -3 ------------ 1 ----------------
\\\\\\\\\\\\\\
x∈[-3; 1]
б)
(x-1)(x+2)(x-4)<0<br>x=1 x= -2 x=4
- + - +
--------- -2 -------------- 1 --------------- 4 --------------
\\\\\\\\\\ \\\\\\\\\\\\\\\\\\
x∈(-∞; -2)U(1; 4)