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[parisse]

Run cardan(3*x^3+2*x^2+x+d,x) but don't try to simplify the answer!
By the way I just checked on a nspire: l:=zeros(x^3+x+d,x), then l[1]^3+l[1], you don't get -d back. If you enter l[1]^3+l[1]+d they return 0, this demonstrate that they are cheating:-)