x} \atop {x^2+6x-3x-18<0}} \right. \left \{ {{-x>5-3} \atop {x^2+3x-18<0}} \left \{ {{x<2} \atop {x1=3; x2=-6}} \right. \right. " alt=" \left \{ {{15x+3-15x-5>x} \atop {x^2+6x-3x-18<0}} \right. \left \{ {{-x>5-3} \atop {x^2+3x-18<0}} \left \{ {{x<2} \atop {x1=3; x2=-6}} \right. \right. " align="absmiddle" class="latex-formula">
X^2+3x-18=0
D=9+72=81
x1=-3+9/2*1=6/2=3
X2=-3-9/2*1=-12/2=-6