If the stone strikes the ground 65 m away, find the time of flight and initial speed?

Vxi = 17.7 m/s

Vyi = 8.636 m/s

xi = yi = 0, yf = -65.0 m, ay = -g, and vi = 19.7 m/s

This is my work so far:
trying to find t: 4.9t^2 - 8.636 -65=0

Then I used the quadratic formula and got t = 4.6285 but it's not right.