Just eyeballing it: 10 only factors into 2 and 5, which doesn't work too well to get a -2. Guess we're doing the hard way. Were you taught the general solution? [-b +/- sqrt(b^2-4ac)]/2a, where a, b and c are the coefficients.
[-(-2) +/- sqrt((-2)^2-4(1)(10))]/2(1)
The part in the square roots is negative, so this equation has no real solutions.