can you please explain this answer?

Answer:
Final velocity = 7.4m/s
Explanation:
Use the equation:
acceleration = (final velocity - initial velocity)/time
Rearrange to get:
final velocity = (acceleration * time) + initial velocity
Now just substitute with the values you already have:
Final velocity = (-9.8m/s^2 * 0.7s) + 0.5m/s
Final velocity = 7.36m/s
We are using 2 sig-figs, so:
Final Velocity = 7.4m/s