x>=3 x^2+x+x-3-21=0 x^2+2x-24=0 x1=4 x2=-6 x=4
x<3 x^2+x+3-x-21=0 x^2-18=0 x1=3sqrt(2) x2=-3sqrt(2) x=-3sqrt(2)
4^2+9*2=16+18=34
x>=3 x^2+x+x-3-21=0 x^2+2x-24=0 x1=4 x2=-6 x=4
x<3 x^2+x+3-x-21=0 x^2-18=0 x1=3sqrt(2) x2=-3sqrt(2) x=-3sqrt(2)
4^2+9*2=16+18=34