at best me kan ges bout the stuf yu rite...dy/dx=3x^2 -6x-3
& yu wanna set it tu zero
first chanj it tu 3*(x^2-2x-1)
then yuze quadratik equashun tu find zeroes...a=1, b=-2, c=-1
roots=2.414213562 & -0.414213562
b^2-41c=8, sqroot(8)=2*sqrt(2)=2.828427125
-b/2a=1, so root/2a=sqrt(2)=1.414213562373055048801688724205...