Essentially, you are being asked to factor
... x^2 +9x -10 = 0
That is, you are looking for factors of -10 that add to +9. It doesn't take long to find that -1 and 10 add to +9, so the factorization is
... (x -1)(x +10) = 0
The solutions are the values of x that make these factors zero.
... x = 1 or x = -10
