For a questions which involves constant acceleration, you can use the SUVAT equations.
S - displacement - -26.5m ( If you to take the right as a positive value - since displacement is a vector quantity involving direction and magnitude)
U
V - Final Velocity - unknown
A - Acceleration - -1.8m/s^2
T - Time - 3.81s
s = vt - 1/2at^2
-26.5m = 3.81v - 1/2 • -1.8 • 3.81^2
Rearrange
-26.5m/-1/2•-1.8•3.81^2=3.81v
3.81v = -2.028~
v = -0.532~ (3sf)
