An object moves with acceleration given by a = -6t^3 m/s^2. Its initial velocity at t = 0 is 5 m/s. How far will it move before stopping?

((((((The answer is " 7.5 m " )))))
Can you please show me the solution.

dv/dt = -6 t^3

v = -(6/4)t^4 + 5
when it stops, v = 0
t^4 = 3.333 seconds to stop
t = 1.351 and t^5 = 4.504

x = -(6/20) t^5 + 5 t

x = -(6/20)(4.504) + 6.755

= -1.3512 + 6.755

= 5.4 meters