I guess this is my last question really don't understand what im writing in wrong when it goes to the quadratic equation.

Below is the question:
A car traveling at a constant speed of 26.7 m/s passes a trooper hidden behind a billboard, as in the figure. One second after the speeding car passes the billboard, the trooper sets off in chase with a constant acceleration of 3.61 m/s2.
(a) How long does it take the trooper to overtake the speeding car?
(b) How fast is the trooper going at that time?

(a) 1/2 a t^2 = v (t + 1) ... .5 * 3.61 * t^2 =26.7 t + 26.7

1.81 t^2 - 26.7 t - 26.7 = 0 ... t = 15.7 s

(b) v = a t = 3.61 m/s^2 * 15.7 s