0}} \right." alt="\left \{ {{x^2+4x-1<0} \atop {x^2+4x+1>0}} \right." align="absmiddle" class="latex-formula">
x²+4x-1<0;</p>
D=16+4=10;
x1=(-4+√20)/2=-2+√5;
x2=-2-√5/2;
+ - +
_____-2-√5_________-2+√5_______
-2-√5
x^2+4x+1>0;
D=16-4=12;
x1=(-4+√12)/2=-2+√3;
x2=-2-√3;
+ - +
_____-2-√3_________-2+√3_______
x<-2-√3;</strong>
x>-2+√3;
x ∈ ∪ ;