2. In a quadratic trinomial, the first coefficient and the constant term were swapped, after which the result was added to the original trinomial. This resulted in a third quadratic trinomial, which turned out to have a single root. What can this root be equal to? If there are multiple correct answers, list them separated by commas or semicolons.
A number or a short expression. Spacing, $ signs and \frac vs / are all fine.
Official solution
Answer: −1,1∣1,−1∣1;−1∣−1;1
Source: NuminaMath-1.5,
licensed Apache-2.0.
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