Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: what is the sum of all possible solutions to the equation √ 2 x ^ 2 − x − 9 = x + 1 ?
5
There is no solution for this equation.