When I solve it with Wolfram Alpha, I get one real root $-1.2414,$ and two complex roots: $0.6207+1.35i$ and $0.6207-1.35i.$ This makes sense.
When I use Cardano's formula in Wolfram Alpha, I get $0.85+1.21i.$ Why is this? Does Cardano's formula always work? I am bewildered.